This finding persisted after controlling for obesity. The decline is likely due to certain chemicals.
Sperm counts and testosterone have been dropping in men for many years. This is what happens when we introduce all of these chemicals into our environment and bodies.
Sperm counts among men in the west have more than halved in the past 40 years and are currently falling by an average of 1.4% a year.
It was a chilling and alarming revelation. Western nations – although not developing countries – appear to be facing disaster. But what could be triggering this decline in sperm? And what can be done to counter it?
The work was an analysis of more than 100 previous studies in the field…Professor Chris Barratt, at Dundee University, described it as a landmark study “that should ring alarm bells”, while Manchester University’s Professor Daniel Brison said its “shocking” results should act as “a wake-up call to prompt active research in the area”.
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.
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.