Testosterone decline over generations

You’re Not The Man Your Father Was

According to a recent report from JAMA, testosterone therapy among American men is on the rise. From 2010 to 2013, prescriptions more than doubled, which researchers partially attribute to ubiquitous drug marketing campaigns urging older men to boost “low T” levels. The swell of interest reflects a genuine physiological shift: Across the population, men today have less testosterone compared to men of the same age a generation ago. Asking why requires untangling a complex web of social, environmental, and behavioral factors that are dismantling age-old ideas about masculinity and triggering real anxiety over changing gender roles.

Studies show that men’s testosterone levels have been declining for decades. The most prominent, a 2007 study in the Journal of Clinical Endocrinology and Metabolism, revealed a “substantial” drop in U.S. men’s testosterone levels since the 1980s, with average levels declining by about 1% per year. This means, for example, that a 60-year-old man in 2004 had testosterone levels 17% lower than those of a 60-year-old in 1987. Another study of Danish men produced similar findings, with double-digit declines among men born in the 1960s compared to those born in the 1920s.

Research shows that testosterone levels have been declining for generations. (Credit: )

The challenges to men’s health don’t end there. Rates of certain reproductive disorders (like testicular cancer) have risen over time, while multiple European studies have found that sperm counts are sinking. These trends coincide with a decline in musculoskeletal strength among young men: In a 2016 study, the average 20- to 34-year-old man could apply 98 pounds of force with a right-handed grip, down from 117 pounds by a man of the same age in 1985. Though grip strength isn’t necessarily a proxy for overall fitness, it’s a strong predictor of future mortality.

What’s behind all the downward trends? The answer is complicated. The decline in testosterone levels is almost certainly linked to higher rates of obesity (which suppresses testosterone) and may be linked to lower rates of smoking in men (since nicotine is a potent aromatase inhibitor). In the 2007 study, however, the age-matched declines persisted after controlling for these variables. Many observers put more weight on increased exposure to environmental toxins, such as pesticides, parabens, and chemicals common in household products like phthalates and bisphenol A.

Also playing a role are long-term shifts in the ways we work and live. Young men are far less likely to hold jobs in manual labor, so they don’t have to be as physically strong as previous generations. Meanwhile, certain forms of close relationships—such as marriage, fatherhood, and increased time spent with children—are causally linked to lower testosterone levels. Yet here again the evidence is muddled: On the one hand, Gen-X and Millennial men are marrying later and having fewer kids. On the other hand, young men today are more likely to live with other people—which may promote prosocial hormones like oxytocin that are natural antagonists to testosterone. And those who are fathers are spending more time with their children.

One reason why it’s so hard to pinpoint what’s driving the declines is the sheer number of factors that could be in play. To account for low testosterone, researchers have cited other lifestyle trends­­ as wide-ranging as increased temperatures in homes and offices, lack of exercise, and even tight underwear. It’s also difficult to establish the direction of causality. Has testosterone declined in response to a changed world, or has the world changed to accommodate less virile men? Or is it both? Take declines in strength, for example: While we know supplementing with extra testosterone by itself increases muscle mass, we also know that strenuous exercise by itself promotes natural testosterone production.

What’s happening to men physically dovetails with a broader story of social transformation. The economy is shifting away from jobs that favor men, like manufacturing, and toward sectors dominated by women. Young men have fallen behind women in educational attainment. They’re increasingly dropping out of the workforce and expressing less work centrality. The anxiety over the state of men mirrors a bigger debate over America’s national identity. Americans have traditionally seen themselves as a “pro-testosterone” nation: restless, striving, and rowdy. Yet in his new book The Complacent Class, Tyler Cowen argues that America is losing the dynamism, mobility, and enterprise that made it special. This anxiety may have even led the old-fashioned, overtly macho President Trump to victory.

The confusion over what masculinity means today is reflected in the conflicted feelings of males now coming of age. Most American Millennial men report feeling pressured to project a traditional image of manhood characterized by traits like toughness, self-reliance, and hypersexuality—but when asked if they wish to emulate these characteristics themselves, the majority don’t. A separate survey asked men to rate themselves on a scale of “completely masculine” to “completely feminine.” Only 30% of 18- to 29-year-olds chose “completely masculine.” That’s compared to 65% of men over 65.

All these social and cultural changes have also left Millennial women in uncharted waters. More face a dating pool where partners of equal education and status are harder to come by, leaving them waiting for men catch up or deciding to go it alone. “They aren’t men,” one young woman told Philadelphia Magazine flatly. “They’re boys.” It’s a sign of a long-term generational reversal: When Boomer women were coming of age, they wanted kinder, gentler men in touch with their feelings. Now Millennial women yearn for guys who can “man up” and take care of business.

Ultimately, it’s impossible to pigeonhole what’s happening to masculinity as wholly positive or negative. The strongest objections come from critics who believe men and women are naturally built for traditional roles—or from those who argue that toxic chemicals are wreaking havoc on men’s health. Those who believe traditional gender roles are dysfunctional, however, welcome moving past them. A less testosterone-laden world might be less aggressive and more emotionally expressive. If there’s one thing on which observers agree, it’s the need for solutions to support the men the 21st-century economy is leaving behind.

Why all men ‘should be concerned about declining testosterone’

There is a strong link between men’s low levels of testosterone and having two or more chronic diseases such as arthritis, high blood pressure, and type 2 diabetes — even in the under-40s.

Share on PinterestHow could having low testosterone levels affect your overall health?

This was the conclusion of a study that, for the first time, examined the relationship between total testosterone, age, and specific chronic conditions in a representative sample of the adult male population of the United States.

“If we look at data for men from a population level,” states lead author Mark Peterson, an assistant professor of physical medicine and rehabilitation at the University of Michigan in Ann Arbor, “it has become evident over time that chronic disease is on the rise in older males.”

He goes on to explain, however, that they are also finding that obesity and physical inactivity may be responsible for testosterone decline “even at younger ages.”

The researchers report their findings in a paper now published in the journal Scientific Reports.

The traditional view of testosterone is that it is mainly involved in sex-specific development of the male human body. However, it is becoming increasingly evident that the hormone plays many different roles, including some that are not sex-related, in both males and females.

We know, for example, that testosterone is important for bone health and cardiovascular function, and that it can have a beneficial impact on “lean muscle mass and body fat.”

Testosterone decline and disease risk

The new study concerns the importance of testosterone in male human health, and what effects might be linked to its decline.

Previous studies have demonstrated that testosterone levels fall in men as they get older, and that deficiency of the hormone is also linked to the sorts of chronic diseases that often accompany obesity.

“But it hasn’t been previously understood,” explains Prof. Peterson, “what the optimal levels of total testosterone should be in men at varying ages, and to what effect those varying levels of the hormone have on disease risk across the life span.”

In their new paper, he and his colleagues note that while “normal ranges” for total testosterone in “young healthy men” have been defined, these are based on studies of groups that are not representative of the “growing, ethnically diverse U.S. population.”

In addition, those studies excluded people with “chronic multimorbidity” — that is, those with more than one chronic illness.

Therefore, Prof. Peterson and colleagues designed their study to examine the relationship between total testosterone deficiency and chronic multimorbidity in “a large, population-representative sample of U.S. men.” They also designed it to look at the effect in different age groups.

Data drawn from national health survey

The team used data from the National Health and Nutrition Examination Survey, which assesses the health and dietary status of the U.S. population using a combination of interviews and physical exams.

Their analysis included 2,161 men aged 20 and older for whom there was complete information on: age and other demographics, diagnosed chronic illnesses, testosterone levels as measured from blood samples, grip strength, and laboratory-confirmed risk factors for cardiometabolic disease.

First, they calculated the prevalence of nine chronic conditions in the representative sample. These were: arthritis, cardiovascular disease, clinical depression, high blood pressure, high cholesterol, high triglycerides, pulmonary disease, stroke, and type 2 diabetes.

They then examined how the prevalence of having two or more of these conditions varied across “young, middle-aged, and older men with and without testosterone deficiency.”

Young men were defined as aged 20–39.9 years, middle-aged men as 40–59.9 years, and older men as aged 60 years and above.

Significant ‘dose-response relationship’

The results from across all age groups revealed that having two or more chronic diseases was more common in men with low total testosterone than in those with normal levels, and it was particularly striking among the young men and older men.

Further analysis showed that there was a significant “dose-response relationship” at play, which Prof. Peterson says “means that men should be concerned about declining total testosterone, even if it has not reached a level to warrant a clinical diagnosis .”

The level of clinical diagnosis he refers to is if total testosterone falls below 300 nanograms per deciliter, or 10.4 nanomoles per liter.

The scientists suggest that while the study does not prove that the decline of testosterone causes chronic diseases, it should prompt further research and expand clinicians’ understanding of the hormone.

They also hope that their findings will raise men’s awareness about testosterone deficiency. “A lot of men may not be aware of the risk factors for testosterone deficiency because of their current lifestyle,” says Prof. Peterson.

“And more importantly, that declining levels could be contributing to a silent decline in overall health and increased risk for chronic disease.”

Prof. Mark Peterson

Where Men Spend Their Childhood Determines Testosterone Level, Study Says

Researchers have long known that the hormone testosterone can rise and fall according to a man’s environment or life situation. Marriage, becoming a father, stress, or even holding a baby doll can all make the presence of the hormone surge or shrink. What scientists haven’t known is why some populations have naturally higher levels of testosterone than others.

New Research Challenges Thinking on the Role of Race, Genes in a Man’s Hormone Levels

A new study out of Durham University in the United Kingdom suggests that the childhood environment of males determines their testosterone level, undermining the previous prevailing theories that race or genes govern the amount of the hormone in each individual.

Related: Testosterone and Men’s Health and Wellness

Living in Impoverished vs. Industrialized Areas May Impact Hormone Levels

Average levels of testosterone can vary widely depending on where men live, according to Kesson Magid, PhD, a biological anthropologist at Durham University and lead author of the study, published this week in Nature Ecology and Evolution. “The typical pattern is higher testosterone in men in richer, post-industrialized countries of Europe or North America compared with men living in poorer parts of the world or places where most of the population faces higher rates of disease,” he says.

According to Magid, the study was designed to compare highly contrasting environments to try to determine the origin of the hormone-level differences. Researchers assumed that there would be few environmental challenges for males in the United Kingdom compared with Bangladesh. “We didn’t know whether these differences were due to how men reacted to their immediate surroundings as adults, or whether these differences were set at an early age, prior to adulthood,” he says.

Related: How Stress Affects Your Body, From Your Brain to Your Digestive System

Who the Researchers Followed — And Why

Bangladesh is among the poorest countries in the world, where the rate of maternal undernutrition and stunting is more than one in three for children less than five years old. To ensure that the results weren’t overly influenced by nutritional deficiencies, researchers studied the middle-class, land-owning part of the population, the people who would normally not be impacted by the environmental effects of extreme poverty.

Related: How Childhood Trauma Could Impact Your Health

Researchers collected data from 359 men who fell into one of five groups: men born and raised in Bangladesh, Bangladeshi men who migrated during childhood to the UK, Bangladeshi men who migrated to the UK as adults, second-generation UK born and raised children of Bangladeshi migrants, and UK-born ethnic Europeans.

Which Men Had the Highest Levels of Testosterone?

Magid and his colleagues found that Bangladeshi men who grew up and lived as adults in the UK had significantly higher levels of testosterone compared with the men who grew up and lived in Bangladesh as adults. The Bangladeshis in the UK also reached puberty at a younger age and were taller than men who lived in Bangladesh throughout their childhood.

Related: Stress-Related Disorders Linked to Autoimmune Diseases, Study Finds

Factors That Determine a Man’s Testosterone Levels

The difference in testosterone levels is due to the amount of energy the body is able to invest in generating the hormone, according to the authors. In Bangladesh, the males needed to expend energy fighting off disease or overcoming poor nutrition during their developmental years. The more energy directed at survival, the less energy remaining for testosterone.

Related: What Are Common Symptoms of Anxiety Disorders?

Childhood Surroundings Influence Hormone Levels Later

“The results of our study support the idea that the environment a man experiences in his youth affects his testosterone levels later in his life,” says Magid, adding that ethnicity or where men live as adults is less likely to impact the hormone’s levels.

“Additionally, it appears that this ‘setting’ of adult testosterone levels doesn’t occur right away in infancy but is determined into later childhood,” he says. “The data suggest that older boys may adjust to their environment into their teens; this was later than I might have expected.”

Genetic Markers Still Influence Testosterone Levels

Genes likely play a part in an individual’s testosterone level, says Magid. “There is a good amount of evidence that testosterone levels within populations do correlate with some genetic markers, and there is some inheritance of testosterone levels down family lines,” he says. This study investigated differences in testosterone between populations, not of the individuals within them, he adds.

Should Some Men Be Tested for Testosterone-Related Conditions?

The health implications of these findings could impact health screenings for some populations. “The result that the UK-born children of migrants had higher levels of testosterone than men with nonmigrant parents suggests that these men may be at greater risk of enlargement of the prostate in later life,” says Magid, adding that these men may need to be especially aware of screening programs for prostate disease. “The next step is to see if these children of migrants have higher incidence of symptoms related to prostate disease, for instance, benign prostate hyperplasia (also known as enlarged prostate),” he says.

Results Raise More Questions About Testosterone Levels Falling in US Men

Does this research provide any insight into why testosterone levels have been in steady decline in the United States for several decades? If a safer, less-challenging environment leads to higher testosterone levels, wouldn’t levels be rising instead of falling?

Magid points to trends toward higher rates of obesity and lower rates of smoking that at least partially explain lower levels of testosterone. “There are a number of theories why this might be occurring, and there are those who dispute whether this is either a real trend or what it could mean for male health in the long term,” he says.

“Whatever the explanation for this trend (lower testosterone levels in the United States), it is independent of growing up in an environment of limited ecological stress, or it is potentially related to having lived under such conditions for multiple generations,” he says.

Will Tomorrow’s Boys Have Lower Testosterone Levels Than Their Fathers?

“It is possible that these effects are being played out in the migrant communities we measured here, in which case we would predict that the children of the children of migrants would have lower testosterone than their fathers, and they might match the lower levels seen in their European neighbors who have also been in the UK for multiple generations,” he speculates.

Testosterone Is Mixed Blessing To Men’s Health

“Men with higher testosterone are less vulnerable to high blood pressure, heart attacks, frequent colds and obesity,” says Dr. Alan Booth, professor of sociology and human development. “In addition, they are more likely to rate their health as excellent or good rather than fair or poor. Studies show self ratings of health correlate highly with physicians’ assessments.

“The benefits of higher testosterone levels have a down side, however,” Booth notes. “Some, but not all, men with higher levels of testosterone are more likely to engage in behavior that cancels out the beneficial effects of testosterone.”

Those with higher levels of testosterone are more inclined to smoke, drink alcohol excessively and indulge in risky behavior that leads to injury. The biggest detriment to health by far is the tendency for high testosterone men to smoke.

Booth; Dr. Douglas A. Granger, assistant professor of biobehavioral health and director of Penn State’s Behavioral Endocrinology Laboratory in the College of Health and Human Development; and Dr. David R. Johnson, professor of sociology at the University of Nebraska-Lincoln, have published their work in the paper, “Testosterone and Men’s Health, in a recent issue of the Journal Of Behavioral Medicine.

The researchers studied testosterone and health in a sample of 4,393 men between the ages of 32 and 44 who had served in the military between 1965 and 1971. The men were interviewed and medically examined. Testosterone was measured in plasma from blood drawn at 8 a.m. Concentrations ranged from 53 nanograms per deciliter (ng/dl) to 1,500 with an average of 679.

“Comparison of men with slightly average levels of testosterone (400/ng/dl) with men with slightly above average levels (800 ng/dl) revealed significant differences in the indicators of health,” Booth says.

Men at the higher level were 45 percent less likely to have high blood pressure, 72 percent less likely to have experienced a heart attack, 8 percent less likely to have 3 or more colds in a year, and 45 percent less likely to rate their health as fair or poor.

On the negative side, men at the higher level were 25 percent more likely to report one or more injuries, 32 percent more likely to imbibe 5 or more drinks in a single day and 151 percent more likely to smoke.

“We don’t yet fully understand how testosterone benefits health or leads to behaviors detrimental to health,” Booth says. “More studies are needed to discover the missing pieces to this puzzle. What is clear is that men with higher testosterone levels are at higher risk for negative health outcomes. But there are many men with higher testosterone who don’t engage in health risk behavior and who do realize testosterone-related health benefits.”

Increasing men’s awareness of their testosterone levels may be worthwhile in terms of health promotion and disease prevention efforts, say the researchers. Regular monitoring of testosterone levels would make it easier to optimize the sensitive balance between testosterone’s positive and negative effects, especially if it is done as part of overall physical checkups.

“Monitoring testosterone through saliva samples is now possible and offers distinct advantages over the traditional means of assaying blood,” Granger notes. “Saliva sampling is non-invasive, samples can be self-collected, repeated samples can be obtained with minimal effort and the accuracy of saliva assays has substantially improved in recent years.”

IAAF Sets New Limits On Testosterone Levels In Women

Caster Semenya of South Africa crosses the line to win gold in the Women’s 800 meters during athletics on Day 9 of the Gold Coast 2018 Commonwealth Games in Australia. Michael Dodge/Getty Images hide caption

toggle caption Michael Dodge/Getty Images

Caster Semenya of South Africa crosses the line to win gold in the Women’s 800 meters during athletics on Day 9 of the Gold Coast 2018 Commonwealth Games in Australia.

Michael Dodge/Getty Images

What exactly makes a woman?

Track and field’s world governing body thinks the answer has to do with levels of serum testosterone, at least when it comes to female runners competing in middle-distance races.

The International Association of Athletics Federation announced a new set of rules Thursday that will ban women who naturally produce higher-than-normal levels of testosterone from participating in races ranging from 400 meters to the mile, unless they agree to take medication.

Athletes with the condition, called hyperandrogenism, would be eligible to compete at the international level only if they reduced blood testosterone levels through the use of hormonal contraceptives, including birth control pills.

The rule will go into effect on Nov. 1.

“Our evidence and data show that testosterone, either naturally produced or artificially inserted into the body, provides significant performance advantages in female athletes,” said IAAF President Sebastian Coe in a statement.

“The revised rules are not about cheating, no athlete with a has cheated, they are about levelling the playing field to ensure fair and meaningful competition in the sport of athletics where success is determined by talent, dedication and hard work rather than other contributing factors,” he added.

The new stipulations are stricter than those established by the IAAF in 2011, which limited women’s testosterone levels to 10 nanomoles per liter of blood. The new requirements reduce the limit by half to 5 nanomoles per liter.

That is still far above levels in most women, including elite female athletes, whose levels range from 0.12 to 1.79 nanomoles per liter, states a 22-page IAAF document defending the organization’s decision. Meanwhile, the normal male range after puberty is much higher, from 7.7 to 29.4 nanomoles.

“Therefore, a concentration of 5 nmol/L is an appropriate decision limit for purposes of these Regulations,” the IAAF stated.

As NPR reported, the IAAF’s first effort to restrict some female athletes was struck down by the Court of Arbitration for Sport after a challenge by Indian sprinter Dutee Chand, who was prohibited from racing after a hormone test. In its decision, the CAS wrote it “was unable to conclude that hyperandrogenic female athletes may benefit from such a significant performance advantage that it is necessary to exclude them from competing in the female category.”


Caster Semenya: ‘It’s All About Loving One Another’

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The latest guidelines are the result of two years of scientific research by the organization, including a 2017 study commissioned by the IAAF containing what it said is evidence connecting high testosterone level and improved performance.

Other conditions established by the organization: Female athletes must maintain testosterone levels within the new limits for at least six months and must maintain them continuously, whether in competition or out.

Under these rules all hyperandrogen athletes who refuse to take drugs to alter their body’s natural testosterone production can move into either shorter or longer-distance running, participate in noninternational races, or race against men.

Athletes participating in the 100m, 200m and 100m hurdles are exempt, as are races longer than 1 mile and field events.

South African Olympian Caster Semenya is expected to be among those affected by the changes.


— Caster Semenya (@caster800m) April 26, 2018

Shortly after the announcement Semenya took to Twitter with a post that read, “I am 97% sure you don’t like me, but I’m 100% sure i don’t care,” and ended the note with a slightly angry frowny-face emoji.

The two-time gold medalist and three-time world champion has been at the center of the fairness and testosterone debate since she began dominating the 800-meter race on the world scene as a teenager in 2009.

Everything about her speed, the way she looked — broad shoulders, narrow hips, prominent Adam’s apple — and the way she spoke, in a deep voice, prompted her competitors to openly question Semenya’s sex.

As a result she was subjected to invasive sex verification tests that ultimately (after being leaked) revealed she had testosterone levels three times higher than most women.

During the four-year period when the IAAF had imposed its testosterone level limits, Semanya continued to rank among the world’s fastest middle-distance runners, though her speed was not as explosive as it had been before the policy was implemented. And in 2015, she failed to make the world final.

Neither Semenya nor the IAAF has ever confirmed that she was forced to suppress her natural hormone production. But when the policy was lifted Semenya’s running time improved to her pre-restriction levels, Deadspin reported.

Athletics South Africa released a statement Thursday stating it would seek advice from the nation’s Sport Ministry on how to handle the issue, adding that it will support “all our athletes who may be affected by this new ruling.”

Athletics South Africa has responded to the @iaaforg new female testosterone regulation laws that are set to come into effect on 1st November. pic.twitter.com/xEG382T9iU

— EWN Sport (@EWNsport) April 26, 2018

Meanwhile, the African National Congress reacted in a less restrained manner, saying the IAAF’s regulations intentionally target Semenya and are unfair and racist.

“The ANC has always understood sport as a unifier and a tool to bring people and nations together. It is for this reason and many that the ANC cannot ignore the attempt by the IAAF to discriminate and exclude athletes. These new regulations infringe on the Human Rights of athletes, targeting mainly those in East Europe, Asia, and the African continent. The racial undertones of this cannot go unnoticed,” it said in a statement.

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