Men's testosterone levels have declined by 54% since 1972: Study
What's the story
A recent study has revealed a shocking decline in men's average testosterone levels over the past five decades. The research, presented at the annual meeting of the European Society of Human Reproduction and Embryology in London, found that total testosterone levels in men have declined by a staggering 54% between 1972 and 2019. The findings suggest a major crisis in male reproductive health, with obesity and diabetes playing a part.
Possible causes
Environmental factors also contributors
Along with obesity and diabetes, the study also hints at environmental factors as possible contributors to this decline in testosterone levels. These include endocrine-disrupting chemicals found in many household products and global warming. Professor Hagai Levine from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Israel, who led the study, stressed that this is not a statistical error but a strong trend indicating a major crisis in male reproductive health.
Hormonal impact
Complications of low testosterone levels
The relationship between testosterone and health is complex. The hormone regulates sperm production, sex drive, muscle mass, bone density, mood, energy levels, and metabolism. Health factors like obesity can lower testosterone by increasing body fat that converts testosterone into estrogen. There's also a medical debate over testosterone supplements which can suppress sperm production despite their intended purpose of boosting testosterone levels in men with low counts.
Research details
Details of the meta-analysis
The meta-analysis in question combined six previous longitudinal studies tracking testosterone levels, each with at least three time points. The data came from 118,593 individuals across Israel, the US, Brazil, Finland, and Denmark between 1972 and 2019. All individual studies found a decline in testosterone levels. When combined, the overall drop was estimated at 54%, with an acceleration after 2000.
Health factors
Need for more research
Professor Levine speculated that obesity and metabolic syndrome could explain one quarter to one half of the testosterone decline. However, others like Professor Channa Jayasena from Imperial College London, a consultant in reproductive endocrinology, said it would be premature to conclude this without further research. Jayasena stressed the need to clarify if environmental factors are also contributing to this decline along with obesity and diabetes.