Environmental factors of obesity

ORIGINAL ARTICLE

Obesity as risk factor associated with hypertension among nursing professionals of a national philanthropy health institution

Obesidad como factor de riesgo para la hipertensión entre profesionales de enfermería de una institución filantrópica

Aline Furtado Carlos de OliveiraI; Maria Suely NogueiraII

IMaster Student at Ribeirão Preto College of Nursing, University of São Paulo. Nurse, Coordinator of the General ICU at Irmandade de Misericórdia Hospital in Sertãozinho. Sertãozinho, SP, Brazil. [email protected]
IINurse. Associate Professor of the Department of General and Specialized Nursing. Ribeirão Preto College of Nursing, University of São Paulo. Ribeirão Preto, SP, Brazil. [email protected]

Correspondence addressed to

ABSTRACT

The present study analyzed the relationship between obesity and high blood pressure among nursing professionals of a philanthropic institution, with a view to the early detection of possible cases of hypertension. The study population consisted of 147 nursing professionals of ages between 20-70 years. The researcher performed structured, individual, interviews at the work site of those professionals, 91.8% of which were women; 29.2% were older than 40 years; 11.6% had a SBP>140mmHg and 6.8% DBP>90mmHg; 12.2% had obesity class I-II; 38.1% of women with a WHP>0.85, 12.2% in the age range of 40-49 years; 2.1% of men with a WHR>1.0, 1.4% in the age range of 40-49 years. It was found that, though nursing professionals know the severity of the disease and the importance of changing their life habits, they still find it difficult to adopt that behavior, which suggests the need to implement educational programs at the work site to help them to change their behaviors.

Key words: Nursing. Obesity. Hypertension. Risk factors. Voluntary Health Agencies.

RESUMEN

Se analizó la presencia de obesidad relacionada con niveles de presión alterados, entre los profesionales de enfermería de una institución filantrópica, con el propósito de observar la detección precoz de posibles hipertensos. La población estuvo constituida por 147 profesionales de enfermería con edades de entre 20 y 70 años. El investigador realizó una entrevista estructurada, individual en el local de trabajo de dichos profesionales; 91.8% eran mujeres; 29.2% tenían edad superior a 40 años; 11.6% fueron identificados con PAS>140mmHg, 6,8% con PAD>90mmHg; 12.2% presentaron obesidad de grado I-II; 38.1% de las mujeres, RCQ> 0.85, 12,2% con edad entre 40-49 años; 2.1% de los hombres presentaron RCQ>1.0, 1.4% se encontraban en la faja etaria de 40-49 años. Es posible identificar que a pesar de que los profesionales de enfermería conozcan la gravedad de la enfermedad y la importancia de cambios en los hábitos de vida, aún muestran dificultad para adoptar tal comportamiento, lo que sugiere la necesidad de la implementación de programas educativos en los locales de trabajo con el objeto de facilitar cambios en el comportamiento de estos profesionales.

Descriptores: Enfermería. Obesidad. Hipertensión. Factores de riego. Agencias Voluntarias de Salud

INTRODUCTION

Systemic Arterial Hypertension (SAH) refers to the chronic increase of systolic blood pressure (SBP) or diastolic blood pressure (DBP). The diagnosis for SAH can only be established when at least three measurements are performed, with an one-week interval between them, and if SBP values above 140 mmHg or DBP values above 90 mmHg are identified, considering adult individuals older than 18 years. When it is identified that the SBP is equal to or greater than 210 mmHg or DBP equal to or greater than 120 mmHg, more than one measure is necessary to implement the treatment(1).

Increases in weight and waist circumference (WC) are important prognostic indexes for SAH, as central obesity is an important indicator of cardiovascular risk; 75% of men and 65% of women present SAH directly attributed to overweight and obesity(2).

The Body Mass Index (BMI) is obtained by dividing the weight, in kilograms, by the height, in square meters. The WC can be measured from the mean point between the iliac crest and the lowest rib and the hip circumference (HC) is usually measured at the height of the femoral trochanters, with waist-hip ratio values (WHR) above 0.85 for women and above 1.0 for men(3).

Regardless of the degree of overweight, excessive abdominal fat can be evaluated using the WHR, and it is an important risk factor for several non-infectious chronic diseases(4). The BMI together with age and gender are considered the variables that most affect body fat distribution.

The risk of developing chronic-degenerative diseases, such as cardiovascular disease, SAH, diabetes mellitus (DM) and dyslipidemia appears to increase progressively when the BMI achieves levels above 25 kg/m2, and with WC above 94 cm for men and above 80 cm for women(3-5).

Fat intake in individuals with SAH should be reduced, because the complications may increase, such as coronary artery disease (CAD), besides the fact that obesity, alone, increases tension values.

OBJECTIVE

To analyze the presence of obesity associated with altered blood pressure levels among the nursing workers of a philanthropy institution, in view of early detection of possible hypertension cases.

METHOD

This is a descriptive study, which used a quantitative approach, performed with nursing workers (nurses, nursing technicians and aides) of a philanthropy institution located in the interior of São Paulo state.

The study population consisted of nursing workers of both genders and with ages ranging between 20 and 70 years, who performed everyday activities and agreed to participate in the study by signing the Free and Informed Consent Form, after it being approved by the Research Ethics Committee at Ribeirão Preto College of Nursing, University of São Paulo (EERP/USP) (Document number 0494/2004).

Data were collected by means of structured interviews, according to the instrument used by Simão, which includes data regarding the Health Field model (6-7).

The data collection instrument includes items of human biology, which comprises data regarding their identification, anthropometric data (weight, height, blood pressure values) and family background; environment, including data regarding the individual’s education, professional practice, family structure; life style, which refers to aspects concerning exercising, eating habits, smoking, consumption of alcoholic beverages, etc; health service organization, which comprises the information regarding the use of health services, treatments for diseases and use of medications.

Blood pressure (BP) values were identified by using the indirect method, using cuffs with a rubber bag, with width that was compatible with the mid-upper arm circumference of individuals(8-9). Data analysis was performed considering the BP value obtained from the mean value from the two measurements.

RESULTS AND DISCUSSION

Besides the age, we observed the body weight of the population, which ranged from 45 to 130 Kg, with an average of 87.5 Kg. As for their height, it ranged between 156 and 192 cm, with an average of 174 cm.

Collecting data regarding weight and height was helpful in investigating the presence of obesity among the interviewees, as it is considered a risk factor for cardiovascular diseases (CVD).

Excessive body weight in the abdominal region, evidenced by a WHR above 0.80 in women and 0.90 in men, means a greater risk for SAH, dyslipidemia, DM and mortality by CVD(10).

Previous studies found that obesity was more common among women with elevated WC and WHR(11, 12-13).

The waist and hip circumference measurements are usually the values used to characterize the accumulation of abdominal fat, by means of the WC and the WHR.

The WHR has shown correlation with several diseases, especially those characterized by the metabolic syndrome(14).

Obesity is often associated with insulin resistance, and can cause glucose intolerance and type 2 diabetes, thus considerably increasing the risk to cardiovascular diseases. Weight reduction by following a low-calorie diet, associated to exercising, increases the tolerance to glucose and sensitivity to insulin(2).

It is estimated that there are, currently, 100 million of obese individuals in the world. The prevalence of obesity among individuals with hypertension is considerably greater compared to individuals with normal blood pressure. Literature reports increases three to eight fold in the SAH in obese individuals(14).

Table 4 shows that 61 (41.5%) workers had a BMI > 25 Kg/ m2, 10 (6.9%) of whom had SBP > 140 mmHg and 6 (4.2%) had moderate obesity.

Regarding DBP, the data on Table 5 show that among the workers with BMI > 25 Kg/ m2, 5 (3.4%) of them had DBP > 90 mmHg, and most had a BMI between 30 and 39.9 Kg/ m2 characterizing moderate obesity.

A previous study found a positive association between elevated BMI and the prevalence of SAH(15). Excessive body mass is a predisposing factor for hypertension, and may account for 20% to 30% of hypertension cases(9).

It is important to stress that a great number of professionals work 6 to 12 hours/day, and that work overload eventually triggers several problems in their lives, including wrong eating habits, few hours of sleep, stress, lack of exercise, obesity, and other risk factors predisposing for diseases such as SAH and CVD.

Countries have different socioeconomic levels and risk factors, considering the particularities of each country; it is most likely that people from higher social classes in developed countries have a better control of their health, eating healthy foods, smoking less, and exercising, while the opposite probably occurs among the lower socioeconomic levels, i.e., people eat more animal source foods, saturated fat, sugar and have less time to exercise(16).

An important aspect concerning life style is exercise. However, in this study, it was observed that only 41 (27.9%) of the 147 interviewees did some kind of physical activity, including walking 20 (13.6%), 12 attending the gym (8.2%), playing soccer 4 (2.7%), swimming 3 (2.0%) and cycling 2 (1.4%), against 106 (72.1%) who reported they did not exercise at all. As for the frequency and duration of the physical activity, 14 (9.5%) workers reported they exercised less than three times a week for more than 45 minutes each time, and 11 (7.4%) exercised three times a week for more than 45 minutes each time; among the individuals who exercised regularly, 19 (12.9%) have exercised for less than one year, and 12 (8.2%) reported they have exercised for one to five years. These data clarify that few workers exercise regularly for over a year, indicating that this population has a sedentary lifestyle, which is an important factor for the development of CVD and hypertension.

Exercises should be performed according to the age and health conditions of each individual, two or three days a week and with a duration of 45 to 60 minutes; to do this, patients should be encouraged and require a follow up system to achieve the expected results regarding BP control(17).

Regular physical activity is very important and adds many benefits to life, including the reduction in CVD incidence, because in addition to reducing blood pressure and body weight, it also reduces the risk of developing hypertension in individuals with normal blood pressure(17).

Having a sedentary life style is one of the main causes for maintaining a high body weight, and the latter can cause other serious problems. Exercising has a positive effect on the risks for cardiovascular diseases, on primary or complementary treatment of arteriosclerosis, on reducing lumbar pain, and on diabetes, in addition to having positive short term psychological effects (improved self-image, mood and self-esteem) as long term benefits (reduced anxiety, stress and depression)(18).

The influence of body fat distribution on the prevalence of SAH among obese individuals was confirmed by a 23.0% increase in individuals with overweight and 67.1% in individuals with class III obesity(19).

The data above show that there are a great number of workers at the institution with elevated WHR values who do not exercise, particularly women, who are a majority in the institution.

Several studies have shown that exercising has a hypotensive effect in patients with hypertension, after a single aerobics exercise session, and that the referred reduction in pressure levels is maintained during a physical training program(20).

As for eating habits, 131 (89.1%) workers referred having a good appetite and that the food they eat on a daily basis include red meat, fried foods, pasta, vegetables, milk and coffee; as for their consumption of canned foods and cold meats, 36 (24.5%) workers denied consuming; 90 (61.2%) reported consuming only once/week, and 15 (10.2%) reported consuming 2 to 3 times/week; as for the consumption of fruits and vegetables, most workers reported a consumption of at least two to three times/week, while 13 (8.8%) reported they did not consume the referred foods; as for the use of saturated fat and oils in the preparation of foods, 47 (32.0%) workers reported they use once/week; 60 (40.8%) use 2 to 3 time/week; 24 (16.3%) workers use 4 to 6 times/week and 9 (6.1%) workers referred they did not use any type of fat in their food. Furthermore, also regarding the use of fat to prepare foods, 131 (89.1%) individuals reported they prepared their food exclusively with vegetable source fat; 15 (10.2%) with both animal and vegetable source fat, and only 1 (0.7%) with animal source fat.

The consumption of chocolate and its products was also reported as part of the workers’ eating habits, with 3 (2.0%) reporting they did not consume any chocolate; 89 (60.6%) reported consuming at least once/week, and 48 (32.7%) workers reported they consumed between two to three times/week; as for the consumption of fibers present in bread, cereals and pasta most workers reported they consumed more than twice/week, and 45 (30.6%) workers stated they consumed on a daily basis; 39 (26.5%) workers reported they enjoyed salty foods against 108 (76.5%) workers who stated they did not enjoy salty foods; 45 (30.6%) workers mentioned they had the habit of taking a saltshaker to the table at meals.

For a meal to be healthy it should be sufficient, which implies the amount of food should cover the energetic needs of the body and maintain its balance; it should be complete, as it should provide all the necessary nutrients for the body to function properly, and they should be provided in appropriate, harmonic and adequate amounts.

FINAL CONSIDERATIONS

The interest in studying the risk factors for hypertension disease among nursing workers emerged from observing, within this philanthropy institution where I work, the number of obese and sedentary individuals, besides the great number of medical certificates for cardiovascular problems.

The study was important, because most individuals with hypertension and likely to develop hypertension recognized they needed to take care of themselves and made changes to some of their habits, such as beginning to exercise, changing their eating habits, reduce their consumption of cigarettes and alcoholic beverages, and changed their sleeping habits. Furthermore, they recognized it was easier for them to obtain faster treatment because they worked in the health area and had knowledge about the referred problem.

Nursing workers should consider that in the next three or four decades the current young adult population in Brazil will become the aged population in the country, with a potential for developing chronic diseases, many due to cardiovascular risk factors. Some of those diseases already act silently, initiating a path that can affect the quality of life and the aging process of the population.

Health education is one of the main elements to improve the life conditions of individuals with CVD. The monitoring of risk factors performed by nursing workers is of utmost importance, as it helps to identify the aspect related to improving the health and life conditions for individuals who live with cardiovascular problems.

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2. Sociedade Brasileira de Hipertensão. Sociedade Brasileira de Cardiologia. Sociedade Brasileira de Nefrologia. V Diretrizes Brasileiras de Hipertensão Arterial. Campos do Jordão; 2006.

4. Afonso FM, Sichieri R. Associação do índice de massa corporal e da relação cintura/quadril com hospitalizações em adultos do município do Rio de Janeiro, RJ. Rev Bras Epidemiol. 2002;5(2):153-63.

5. Goulart AC, Benseñor IJM. Obesidade e hipertensão. Rev Bras Hipertensão. 2006;9(1):27-30.

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8. Sociedade Brasileira de Hipertensão. Sociedade Brasileira de Cardiologia. Sociedade Brasileira de Nefrologia. III Consenso Brasileiro de Hipertensão Arterial. Campos do Jordão; 1998.

9. Mion Junior D, Pierin AMG. Manual prático de medida da pressão arterial. São Paulo: Sociedade Brasileira de Hipertensão; 2000.

10. Rosa RF, Franken RA. Tratamento não farmacológico da hipertensão arterial. In: Timerman A, César LAM. Manual de cardiologia. São Paulo: Atheneu/SOCESP; 2000.

16. Marmot MG, Bosma H, Hemingway H, Brunner E, Stansfeld S. Contribution of job control and other risk factors to social variations in coronary heart disease incidence. Lancet. 1997; 350(9073):235-9.

17. Reza GC. O cotidiano do hipertenso na perspectiva do Modelo de Campo de Saúde de Lalonde . Ribeirão Preto: Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo; 2007.

18. Brasil. Ministério da Saúde. Secretaria de Políticas de Saúde. Departamento de Ações Programáticas Estratégicas. Plano de Reorganização da Atenção à Hipertensão Arterial e ao Diabetes Mellitus. Brasília; 2002.

19. Carneiro G, Faria AN, Ribeiro Filho FF, Guimarães A, Lerário D, Ferreira SR, et al. Influência da distribuição da gordura corporal sobre a prevalência de hipertensão arterial e outros fatores de risco cardiovascular em indivíduos obesos. Rev Assoc Med Bras. 2003; 49(3):303-11.

Correspondence addressed to:
Aline Furtado Carlos de Oliveira
Rua Guilherme Volpe, 678 – Jardim Recreio
CEP 14170-060 – Sertãozinho, SP, Brazil

Received: 10/07/2008
Approved: 06/01/2009

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Many factors influence body weight-genes, though the effect is small, and heredity is not destiny; prenatal and early life influences; poor diets; too much television watching; too little physical activity and sleep; and our food and physical activity environment.

What Tips the Scales Toward Excess Weight?

The causes of obesity are as varied as the people it affects.

At its most basic, of course, obesity results when someone regularly takes in more calories than needed. The body stores these excess calories as body fat, and over time the extra pounds add up. Eat fewer calories than the body burns, weight goes down. This equation can be deceptively simple, though, because it doesn’t account for the multitude of factors that affect what we eat, how much we exercise, and how our bodies process all this energy. A complex web surrounds a basic problem.

What are some of the factors that increase the risk of obesity?

Genes Are Not Destiny

Heredity plays a role in obesity but generally to a much lesser degree than many people might believe. Rather than being obesity’s sole cause, genes seem to increase the risk of weight gain and interact with other risk factors in the environment, such as unhealthy diets and inactive lifestyles. And healthy lifestyles can counteract these genetic effects.

Prenatal and Postnatal Influences

Early life is important, too. Pregnant mothers who smoke or who are overweight may have children who are more likely to grow up to be obese adults. Excessive weight gain during infancy also raises the risk of adult obesity, while being breastfed may lower the risk.

Unhealthy Diets

What’s become the typical Western diet-frequent, large meals high in refined grains, red meat, unhealthy fats, and sugary drinks-plays one of the largest roles in obesity. Foods that are lacking in the Western diet-whole grains, vegetables, fruits, and nuts-seem to help with weight control, and also help prevent chronic disease.

Too Much Television, Too Little Activity, and Too Little Sleep

Television watching is a strong obesity risk factor, in part because exposure to food and beverage advertising can influence what people eat. Physical activity can protect against weight gain, but globally, people just aren’t doing enough of it. Lack of sleep-another hallmark of the Western lifestyle-is also emerging as a risk factor for obesity.

Toxic Environment-Food and Physical Activity

As key as individual choices are when it comes to health, no one person behaves in a vacuum. The physical and social environment in which people live plays a huge role in the food and activity choices they make. And, unfortunately, in the U.S. and increasingly around the globe, this environment has become toxic to healthy living: The incessant and unavoidable marketing of unhealthy foods and sugary drinks. The lack of safe areas for exercising. The junk food sold at school, at work, and at the corner store. Add it up, and it’s tough for individuals to make the healthy choices that are so important to a good quality of life and a healthy weight.

Obesity and its causes have, in many ways, become woven into the fabric of our society. To successfully disentangle them will take a multifaceted approach that not only gives individuals the skills to make healthier choices but also sets in place policy and infrastructure that support those choices.

Read more: Obesity prevention

Environmental Factors

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Social and physical environments shape actions and health-related choices of target audiences. Family relationships, neighborhood characteristics, community networks and institutions, regulations, and policies all play a role. An “ecological approach” to obesity examines how these contexts influence one another and helps map out strategies to address problems at each level.

To prevent obesity, barriers to healthy eating and physical activity must be addressed to make the healthy choice the easy choice. Complementary strategies can shift social norms to support healthy behaviors and help people make healthy choices. These strategies should:

  • Increase individual knowledge and skills
  • Change organizational practices
  • Educate community and healthcare service providers
  • Build coalitions and networks
  • Foster policy and environmental change

Social-ecological Model
Many factors contribute to overweight and obesity. The social-ecological model describes factors on the individual, social, community, and societal levels that contribute to poor health outcomes. Figure 3-1 addresses specific assets and barriers to obesity prevention efforts in a rural context. It shows that rates of overweight and obesity in the population are shaped by individual and environmental factors as well as ecological contexts that unfold over the life course.

Figure 3-1: Social-ecological model of obesity prevention in a rural context

Source:Phase I Report: Recommendations for the Framework and Format of Healthy People 2020; The Secretary’s Advisory Committee on National Health Promotion and Disease Prevention Objectives for 2020, U.S. Department of Health and Human Services, October 28, 2008

New evidence is confirming that the environment kids live in has a greater impact than factors such as genetics, insufficient physical activity or other elements in efforts to control child obesity. Three new studies, published in the April 8 Pediatrics, land on the import of the ‘nurture’ side of the equation and focus on specific circumstances in children’s or teen’s lives that potentially contribute to unhealthy bulk.

In three decades child and adolescent obesity has tripled in the U.S., and estimates from 2010 classify more than a third of children and teens as overweight or obese. Obesity puts these kids at higher risk for type 2 diabetes, cardiovascular disease, sleep apnea, and bone or joint problems. The variables responsible are thought to range from too little exercise to too many soft drinks. Now it seems that blaming Pepsi or too little PE might neglect the bigger picture.

“We are raising our children in a world that is vastly different than it was 40 or 50 years ago,” says Yoni Freedhoff, an obesity doctor and assistant professor of medicine at the University of Ottawa. “Childhood obesity is a disease of the environment. It’s a natural consequence of normal kids with normal genes being raised in unhealthy, abnormal environments.” The environmental factors in these studies range from the seemingly minor, such as kids’ plate sizes, to bigger challenges, such as school schedules that may keep teens from getting sufficient sleep. But they are part of an even longer list: the ubiquity of fast food, changes in technology, fewer home-cooked meals, more food advertising, an explosion of low-cost processed foods and increasing sugary drink serving sizes (pdf) as well as easy access to unhealthy snacks in vending machines, at sports games and in nearly every setting children inhabit—these are just a handful of environmental factors research has linked to increasing obesity, and researchers are starting to pick apart which among them play bigger or lesser roles in making kids supersized.

Size matters in “obesogenic environments”
In one of the three new studies dishware size made a big difference. Researchers studied 42 second-graders in which the children alternately used child-size 18.4-centimeter (7.25-inch) diameter plates with 237-milliliter (8-ounce) bowls or adult-size 26-centimeter (10.25-inch) diameter plates with 473-milliliter (16-ounce) bowls. Doubling the size of the dishware, the researchers found, increased the amount of food kids served themselves in a buffet-style lunch line by an average of 90 calories. They ate about 43 percent of those extra calories, on average.

Although kids can typically adjust their energy intake by regulating their food, Temple University public health professor Jennifer Fisher says, their surroundings and options may change that equation for kids in the same way that it does in adults. “This notion that children are immune to the environment is somewhat misguided,” says Fisher, who headed up the study. “To promote self-regulation, you have to constrain the environment in a way that makes the healthy choice the easy choice.”

Fisher says much recent research in nutrition has focused on the “obesogenic” environments of today’s society: a dietary environment offering widespread access to highly palatable foods in large portion sizes. “If we look at adult studies on dieting and weight loss, we know that the prospect of maintaining self-control in this environment is fairly grim,” Fisher says. “I think most scientists believe our bodies have evolved to pretty staunchly defend hunger and prevent weight loss, and maybe are not so sensitive in preventing overconsumption.”

Link between obesity and screen time
Overconsumption might be a key component in the link between obesity and screen time, too, according to another of the new studies. Although past research already had linked increased TV time to widening waistlines, this study dug deeper. Ninety-one 13- to 15-year-olds filled out diaries for TV, video games and computer use during a one-week period. About four to seven times a day the teens were paged to record what they were paying the most attention to at that particular moment, followed by activities receiving their second- and third-most attention. “Kids live in a multitasking world,” says Harvard Medical School pediatrics professor David Bickham, lead author of the screen-time study. “We’re trying to assess their technology use when they’re using different forms of technology at once.”

Bickham says three theories have been floated for the link between screen time and obesity: food advertising, unconscious eating and displacement—that is, the idea that the media use replaces physical activity. His team’s findings lent more support to the first two variables and less to the third. They found video games and computer use had no impact on BMI (body mass index). Television did, but only if it was the main event. Background TV, for example, didn’t matter.

“We’re saying the level of attention may make a difference,” Bickham says. “You have to pay attention to advertising for it to have the impact, and advertising is much less common in computers and video games. In terms of unconscious eating, when you’re watching TV, your hands are free and you’re stimulating your senses with the TV, so concurrent eating is more likely to happen.” Previous research (pdf) has found support for both these theories, such as a study earlier this year showing that neighborhoods with more food and soft drink outdoor advertising had higher rates of obesity. Freedhoff adds that even viewing commercials for fruits and vegetables has been shown to increase consumption of unhealthy foods. “Our hunger hormones have been honed after millions of years of dietary insecurity, so when we want to eat, we tend not to crave green leafy salads,” he says.

Less physical activity is not the problem
The screen-time study did find that kids engaged in more physical activity had lower BMIs, but that does not mean that more exercise is keeping those teens lighter, Freedhoff says. “What we’ve seen for so many years is research looking at physical activity as the preventative or the curative solution for childhood obesity, but the data on physical activity as a means to set children’s weight is abysmal,” he says. “What this study confirmed is that screen time increases obesity consequent to calorie intake, not to a lack of physical activity. That’s a crucial message that people don’t understand—obesity is not a disease of inactivity.”

The third new study, looking at the link between sleep duration and obesity in teens, further blunts the idea that physical activity accounts for much of the increase in kids’ weight. Researchers tracked nearly 1,400 teenagers from ninth through 12th grade and found, like past studies, that less sleep translates to higher BMIs. By analyzing BMI distribution rather than using cutoff points, University of Pennsylvania postdoctoral fellow Jonathan Mitchell says his team detected much stronger sleep effects among already obese teens. The effect of each additional hour of sleep among teens in the 90th BMI percentile was twice as big as among those in the 10th percentile. Increasing sleep from 7.5 to 10 hours a day among 18-year-olds could shave four percentage points off the proportion of teens with a BMI over 25, the researchers predicted.

They also looked at the teens’ physical activity levels. “If you’re sleeping less, you’re fatigued during the day and less likely to be active,” Mitchell says. “But the link we observed was not fully explained by lower levels of physical activity.” Another possibility is that being awake longer means more opportunities to eat, but Mitchell’s team did not look at dietary intake. Past research has also found that sleep deprivation might alter the body’s regulation of hormones leptin and ghrelin, which control satiety and hunger. Or, the problem may not the total caloric intake but the timing of eating, Mitchell says. He noted mice studies where the nocturnal critters became obese if they ate during day and night but remained a normal weight if they only ate at night.

Regardless of the mechanism, these findings also support the notion that the entirety of kids’ 21st-century environment—not their self-control or reduced physical activity—is the key culprit in the rise in obesity. “People like to make obesity a disease of blame, but the last 40 years has not seen an epidemic of our children losing willpower,” Freedhoff says. “There are dozens and dozens of these environmental factors. Unless we reengineer our children’s environments, we are not likely to see any changes in children’s weights.”

Freedhoff points to cities such as Philadelphia and New York, where modifying children’s environments, especially in schools, may be responsible for recent reductions in obesity. Philadelphia removed sugary drinks from vending machines in 2004, then reduced snack food serving sizes, removed deep fryers from school cafeterias and replaced whole milk options with 1 percent and skim. Outside of school, more than 600 corner stores participate in the Food Trust initiative to stock their shelves with healthier snacks. New York has instituted new nutrition standards in schools (pdf) and daycare centers, as well as screen-time limits in day cares. The two metropolises also have some of the most comprehensive menu labeling laws in the country.

“This is a lot more complicated than ‘eat less, exercise more,'” Freedhoff says. “If weight management or childhood obesity prevention and treatment were intuitive, we’d have a lot of skinny kids running around.” Freedhoff himself is developing a program for families that focuses on “redrafting” kids’ and families’ environments, starting with more home cooking. “Every parent would die for their child, but most won’t cook for their children on a consistent basis with whole ingredients,” he says.

But Freedhoff also says the problem of increasing childhood obesity cannot be tackled by parents alone. He suggests starting with changes within school boards, sports teams, PTAs and others who already care about kids. “What I’m amazed by is the constant use of fast food to pacify children and reward children—there is no event too small for candy or fast food.” There are many places communities could start: making school lunches healthier, ditching vending machines and access to fast food inside schools, not celebrating sports wins at fast food joints, and ending the use of candy or fast food as rewards, such as “pizza days” and other unhealthy food-themed school events, to name a few. “People don’t appreciate that parents are around children a minority of their days,” he says, so it really will take a village to turn back the clock in terms of kids’ environments. “If we had a time machine, it would be the world’s best weight-loss program,” Freedhoff says. “It’s the world that has changed, not people.”

Obesity/Overweight Risk Factors and Causes

Risk Factors and Causes of Obesity

Many factors can contribute to obesity and overweight, including lifestyle choices (e.g., lack of exercise, too little sleep), medical conditions (e.g., hypothyroidism) and genetics (i.e., heredity). When a person takes in more calories than he or she uses, overweight and obesity result. These excess calories are stored in the body as fat, and unless weight-control strategies are put into place, more and more weight is gained.

People tend to gain weight when they eat high-calorie foods and do not get enough exercise, but there are other contributing factors, including the following:

  • Lifestyle habits often affect calorie consumption and exercise. People may drive instead of walk. Neighborhoods can be unsuitable for significant outdoor activity. Workplaces might have vending machines that offer only high-calorie snacks rather than healthy alternatives. People may not have time to cook low-calorie meals at home.
  • Certain social factors also may be linked to obesity. Poverty, for example, may cause some people to buy high-calorie processed foods because they typically cost less than healthier foods. Opportunities for exercise may be limited if there are no recreation areas in the neighborhood, if the area is considered unsafe or not conducive to activities like walking or jogging, and/or if gym memberships are too expensive.
  • Many people gain weight when they quit smoking. Food often tastes better and nicotine no longer speeds up the calorie-burning process.
  • Alcohol adds calories to the diet, increases appetite, and may interfere with a person’s ability to make good choices about healthy meals and portion sizes.
  • In October 2012, results of a large study indicated that too little sleep can affect the function of fat cells and increase the risk for weight gain and related conditions like type 2 diabetes.

A number of medical factors also contribute to obesity and overweight, including the following:

  • Age (As people age, the amount of calories needed also changes, often due to reduced activity levels and slowed metabolism.)
  • Cushing’s syndrome (This hormonal condition can cause increased fat around the neck and upper body, with thinning arms and legs.)
  • Hypothyroidism (When too little thyroid hormone is produced, the result is a slower metabolism and less energy for exercise.)
  • Medications (Some drugs, such as steroids, certain antidepressants, and medications to control seizures and psychiatric problems can slow down the body’s metabolism, increase appetite, and cause the body to retain more water.)
  • In women, polycystic ovary syndrome (May also result in irregular or missed periods, small ovarian cysts, and high levels of the male hormone androgen.)
  • Psychological/emotional issues (Stress and boredom may lead people to eat more and exercise less.)

Obesity and overweight can be genetic (i.e., run in families). Genes have some control over the quantity and location of stored body fat. Therefore, obese parents are more likely to have obese or overweight children. However, it is important to note related lifestyle habits. If parents prepare high-calorie meals and do not encourage children to exercise, then obesity is likely to develop within the family.

Publication Review By: Karen Larson, M.D.

Published: 15 Nov 2006

Last Modified: 28 Sep 2015

Factors Contributing to Obesity

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Certain features of rural communities make it more challenging for people to eat a healthy diet and to be physically active. These features differ between communities, but include environmental characteristics, access barriers, and population characteristics.

Environmental Characteristics

Environmental characteristics refer to the natural and physical (built) surroundings in which people live their lives. The design and condition of the environment can contribute to rural obesity – for example, by making it more difficult to obtain healthy foods or to be physically active.

Built Environment

The built environment includes homes, schools, workplaces, parks, farms, and roads. Barriers to healthy eating and physical activity in the built environment include:

  • Limited access to public parks
  • Few sidewalks
  • Lack of public transportation
  • Lack of street lighting

Natural Environment

The natural environment includes climate, resources, water, air, and geography. Barriers to physical activity and access to healthy foods in nature include:

  • Harsh weather (e.g., snow, heat)
  • Rough or hilly terrain
  • Remote location, creating long traveling distances

Access Barriers

Access barriers refer to the availability of resources to support a healthy weight and lifestyle. For example, transportation is a key part of access to opportunity, such as the chance to obtain healthy foods, physical activity, and health care, or to travel to jobs or educational institutions. Nearly 40 percent of rural counties have no form of public transportation. Common rural access issues include:

Healthy Foods

  • Higher rates of food insecurity
  • Limited access to grocery stores carrying fresh fruits and vegetables
  • Higher cost of fresh fruits and vegetables

Physical Activity

  • Limited areas and equipment for structured physical activity
  • Lack of funding for public facilities and/or programs

Transportation Options

  • Long travel distances
  • Lack of transportation infrastructure
  • Dependence on driving

Healthcare

  • Fewer healthcare providers
  • Higher rates of uninsured
  • Fewer disease management programs
  • Limited nutrition education

Public Health Resources

  • Sparsely populated areas receive less public health funding
  • Health programs may not be designed to address rural health issues

Population Characteristics

Population characteristics refer to the demographic and socioeconomic qualities of the community. Rural populations tend to be older, poorer, and at greater risk of becoming obese and overweight than their urban counterparts. To learn more, visit the At-Risk Populations section of this module.

Obesity Causes and Risk Factors

Obesity is a complex condition that’s influenced by work habits, commute patterns, and technology.

At the simplest level, obesity is caused by consuming more calories than you burn.

Obesity, however, is a complex condition caused by more than simply eating too much and moving too little.

The environment you live in and your community’s social norms surrounding food, eating, and lifestyle strongly influence what, when, and how much you eat.

Similarly, your environment affects whether, where, and how you are able to be physically active.

Diet and Lifestyle

Changes in American dietary habits and lifestyle have contributed to today’s high prevalence of obesity.

Those changes include:

  • More adults in the workforce, combined with long work hours and commutes, have led to fewer meals prepared at home.
  • More Americans eat more meals in restaurants, which often serve oversized portions of calorie-dense foods.
  • Portion sizes of packaged foods, such as snacks and soft drinks, have gotten larger over the years.
  • Children spend more hours watching television, using computers, or playing electronic games and less time engaging in active play and recreation.
  • Adults have gotten more sedentary as fewer perform physical labor on the job.

Environment

The way communities, workplaces, and schools are structured in much of the United States has contributed to the country’s high rate of obesity.

Some of the changes seen in the past few decades include:

  • Food (especially junk food) is now sold in places such as gas stations and office supply stores that historically did not sell food. The end result is that food is available almost constantly.
  • Food products and restaurants are marketed intensively on television, radio, online, and elsewhere.
  • Many communities have no safe routes for walking or bicycling, or safe places to play outdoors.
  • Most jobs present few opportunities for physical activity.
  • Many schools provide little or no recess periods or gym classes.
  • Poor neighborhoods are often “food deserts,” with no purveyors of fresh, healthy foods.
  • There are many television shows dedicated to food, restaurants, and cooking that show no regard for the health consequences of the food being featured.

Stress

Stress contributes to obesity in a few ways:

  • People who are stressed tend to make bad food choices and to eat too much.
  • Stress causes the release of stress hormones including cortisol, which triggers the release of triglycerides (fatty acids) from storage and relocates them to fat cells deep in the abdomen. Cortisol also increases appetite.

Genes

Some people have a genetic predisposition to being overweight or obese.

However, in most cases, those people do not become obese unless they also have an energy imbalance — meaning they consume more calories than they burn.

A genetic tendency toward obesity often becomes apparent only when a person’s or group’s lifestyle or environment changes significantly.

Genetic syndromes such as Prader-Willi, Alstrom, Bardet-Biedl, Cohen, Börjeson-Forssman-Lehman, Frohlich, and others can also lead to obesity.

Such syndromes are rare, however, and they typically include other abnormalities besides obesity.

Medical Conditions

A variety of medical conditions are associated with being overweight and obese, including:

  • Cushing’s syndrome (a rare syndrome that results from excess production of cortisol by the adrenal glands)
  • Eating disorders, especially binge eating disorder, bulimia nervosa, and night eating disorder
  • Growth hormone deficiency
  • Hypogonadism (low testosterone)
  • Hypothyroidism (underactive thyroid)
  • Insulinoma (a tumor of the pancreas that secretes insulin)
  • Polycystic ovarian syndrome

In some cases it’s not clear whether obesity causes the medical condition, or whether the condition causes obesity.

Drugs That Contribute to Obesity

Certain drugs have been shown to encourage weight gain — often by increasing appetite — and contribute to obesity.

These drugs include:

  • Diabetes drugs, including insulin, thiazolidinediones (Actos and Avandia), and sulphonylureas (glimepiride, glipizide, and glyburide)
  • Drugs for high blood pressure, including thiazide diuretics, loop diuretics, calcium channel blockers, beta blockers, and alpha-adrenergic blockers
  • Antihistamines (used for allergies), particularly cyproheptadine
  • Steroids, including corticosteroids and birth control pills
  • Psychotherapeutic medications, including lithium, antipsychotics, and antidepressants
  • Anticonvulsant drugs (used for epilepsy and some other conditions), such as sodium valproate and carbamazepine

In some cases, other drugs can be substituted for those that encourage weight gain, or a lower dose can be used.

However, don’t stop taking prescribed medications on your own.

Discuss your options with your doctor, and make a decision together about what’s best for you.

If you must take a medicine that increases your appetite, behavioral measures such as learning to count calories and eat slowly can help to limit weight gain.

An excess proportion of total body fat is known as obesity. When someone’s weight is 20% or more above normal weight, the person is considered to be obese. Body mass index, or BMI, is the most common measure of obesity.5 Body fat is not directly measured when calculating BMI, so some people, for example muscular athletes, may have a BMI in the obese category even though they do not have excess body weight.1

For that reason, it is important to note that BMI is not the only way to calculate for obesity. Waist to height ratio and skinfold body fat testing are examples of other ways to measure for obesity. One of the core symptoms of insulin resistance syndrome and cardiovascular disease is abdominal obesity. For men the danger waist measurement is 40+ inches and for women central obesity is signaled by a waist circumference of about 35+ inches. 4 There are many different tools or websites that are available, which will allow you to input your personal data for results of the tests mentioned as well as others

Find your BMI

BMI For Adults Widget

Most often, obesity occurs when you burn fewer calories than you take in. Some of the other causes of obesity can be inactivity, poor or unhealthy eating habits and diet, pregnancy, lack of sleep, certain medications, and specific medical problems such as Prader Willi, Cushing’s syndrome, or Polycystic ovary syndrome. 1

The following are some obesity-related health complications:

Arthritis

  • There is an increased chance of 9 to 13% of developing arthritis, for every 2 pound increase in weight.3

Breathing Difficulties

  • It is more common for obese individuals to have sleep apnea.3
  • There is a higher prevalence of asthma associated with obesity.3

Cancer

  • There is an associated increased risk for certain cancers, including endometrial, colon, gall bladder, prostate, kidney, and post- menopausal breast cancer for those individuals that are overweight or obese.3
  • From age 18 to midlife, women who gain more than 20 pounds double their risk of postmenopausal breast cancer compared to women whose weight remains stable.3

Complications specific to Children & Adolescents

  • Overweight children and adolescents have an increased occurrence of cardiac risk factors such as high cholesterol and high blood pressure, compared to those with a healthy weight.3
  • There has been a dramatic increase in children and adolescents who have type two diabetes, which has been linked to obesity.3
  • There is a 70% chance of becoming an overweight or obese adult if you are an overweight adolescent, and if a parent is overweight or obese, this risk increases to 80%.3
  • There is a significant amount of social discrimination that occurs and is an immediate consequence of being an overweight adolescent.3

Chronic Venous Insufficiency

  • Obesity is an important risk factor for chronic venous insufficiency, which is when the veins cannot pump enough oxygen-poor blood back to the heart. Raised blood pressure, a sedentary lifestyle, and musculoskeletal problems are all complications of obesity. These can lead to the development of chronic venous insufficiency, which can hamper mobility and use of leg muscles. Occurrence of lower limb ischemia and other vascular disorders caused by inadequate blood flow to the extremities is increased in obese patients.4

Diabetes

  • A weight gain of 11 to 18 pounds increases a person’s risk of developing type 2 diabetes to twice that of individuals who have not gained weight.3
  • Greater than 80% of people with diabetes are overweight or obese.3

Fatty Liver Disease and Gallbladder Disease

  • Insulin resistance is a metabolic disorder in which cells become insensitive to the effects of insulin. This is the main cause of non-alcoholic fatty liver. Obesity, in particular central abdominal obesity, is one of the most common risk factors for insulin resistance. Studies indicate a correlation between body mass index (BMI) and degree of liver damage. The worse the liver damage the higher the BMI.4
  • There is approximately 3 times greater risk for gallstones in obese individuals than in non-obese individuals. A rise in body mass index (BMI) appears to correlate with the risk of symptomatic gallstones.4

Heart Disease

  • In individuals with a BMI >25, there is an increased risk for heart disease.3
  • In adults that are obese, high blood pressure is twice as common compared to those at a healthy weight.3
  • High triglycerides and decreased HDL cholesterol are associated with obesity.3
  • An important pre-condition of many strokes is atherosclerosis, or narrowing of the arteries, which may lead to the formation of an arterial blood clot. Lack of exercise, high cholesterol, smoking, and high blood pressure all accelerate atherosclerosis. A high fat diet, lack of exercise, and raised blood pressure are frequently associated with obesity, especially morbid obesity which is now an important secondary risk factor for stroke.4

Premature Death

  • There is an increase in the risk of death even with a moderate weight excess of 10 to 20 pounds, specifically among adults aged 30 to 64 years.3
  • Compared to individuals with a healthy weight, obese individuals with a BMI > 30 have a 50 to 100% increased risk of premature death from all causes.3

Reproductive Complications

  • There is a 10 times increase in risk for maternal high blood pressure and an increased risk of death for both the baby and mother if one is obese during pregnancy.3
  • Gestational diabetes and difficulties with labor and delivery are more likely to occur in women who are obese during pregnancy.3
  • There is an association with infertility and irregular menstrual cycles with obesity in premenopausal women.3

Quality of Life

  • Quality of life can also be affected by obesity, including issues such as depression, shame, physical discomfort, disability, social isolation, lack of participation in family activities, and discrimination. One of the most painful parts of obesity may be the emotional suffering that can occur.4

1. Mayo Clinic. (2011, May 6). Obesity. Retrieved January 11, 2012, from http://www.mayoclinic.com/health/obesity/DS00314

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