The hormone testosterone plays a dynamic role in men’s lives. Levels of testosterone change at different times of the day and at different life stages. Researchers have also found that levels of testosterone can be affected by a man’s weight and by lifestyle choices, and it appears to play a role in whether they develop some health conditions.
Research on testosterone has often used small sample sizes, which can exclude older men, making it difficult to see if results are applicable to men at all ages, or if there is a difference between younger and older men. This research, led by Professor Allan Mazur (from Syracuse University, USA), used data from Understanding Society which includes men aged 16 to 90 years old – a wide age range, right across the lifecourse. Blood samples were taken in the years 2010-2012 and the testosterone level of the men was recorded. The research team were able to use this data to test several previously recorded links and to see if this broad age range made a difference to the results.
What did they find?
- Testosterone does decrease throughout the day. This result was found at all ages, though there was a larger fall in the hormone for men under the age of 25.
- Obesity is associated with lower testosterone. At each age the researchers found that testosterone decreased with rises in obesity. This effect was particularly noticeable in men over the age of 30.
- Testosterone decreases with age, especially for men in their 30s. The Understanding Society data showed that testosterone levels decline steeply at age 30, but there is a ‘bounce back’ effect when men reach their forties and testosterone rises again. From their 50s onwards testosterone levels remain more or less level into old age.
- Married men, particularly young married men, have lower levels of testosterone. Single men have higher levels of testosterone at all ages.
- Smokers have higher testosterone levels at all ages. This difference persists into old age, even as testosterone generally decreases.
- Taking risks isn’t related to testosterone level. The research team looked at men who are risk tolerant and risk averse and found no difference in the testosterone levels between these two groups.
- Low testosterone is related to an increased risk of type 2 diabetes, heart disease and stroke. After age 50 testosterone levels are significantly and sizeably lower for men with ‘metabolic syndronm’ – the aggregate risk factor for heart disease and stroke.
Read the research: Correlates of testosterone change as men age.
Health and wellbeing
