The College of Endocrinology recently published research that suggested that today 30 year old males have 20% less testosterone in their bodies than 20 years ago. From the age of 30 males lose testosterone at a rate of 1.5% - 2% per year.
Low testosterone has a negative impact on almost every system in the male body, from increasing insulin resistance, obesity levels, risk of cardiovascular disease, reducing skeletal muscle mass, decreasing bone density, to increasing the risk of depression, diabetes and cognitive problems.
If 30 year old males are starting the year on year decline 20% lower than ever, the effect could be catastrophic. The increase in male obesity, the increase in skeletal joint issues, back problems, hip replacements would all be expected on the back of a much lower starting point. Adding yet more pain on an over-run NHS system.
Most of the blame here would tend to come from a) more processed food in the average diet b) a less active population c) More stress in life and lower coping mechanisms.