It is well-documented that testosterone levels decline with age in men.
After the age of 40 years, total testosterone decreases on average -4 ng/dL ( -0.124 nmol/L) per year  or 1.6% per year , and bioavailable testosterone by -2 to 3% per year. 
In older men (over 60 years of age), the average rate of decrement in total testosterone levels has been found to be 110 ng/dL every decade.
However, the relative contributions of changes in health and lifestyle to that decline have not been adequately evaluated. A notable study was set out to investigate this...
The objective of this study was to establish the relative importance of aging, health, and lifestyle in contributing to the testosterone decline in aging men.
The consequences of low testosterone levels (aka low-T) have been primarily investigated in middle-age and older men. However, low-T in young men aged 20-39 years can confer health risks as well...
Low total testosterone levels are associated with an adverse blood lipid profile, which includes high TG and low HDL, [1, 2] and a decline in total testosterone levels predisposes men to increased risk of cardiovascular disease (CVD) and mortality.[3-7]
1 in 3 US adults aged 40-59 years has high blood pressure (hypertension); among those over 60 years of age the prevalence is over two-thirds, 67%. High blood pressure is a well known risk factor for cardiovascular disease; the leading cause of death worldwide.[1, 2] As two-thirds of sudden cardiac deaths occur in clinically healthy individuals , novel indicators of early recognition of adverse cardiometabolic risk in disease-free adults are clearly needed. It has been demonstrated that healthy disease-free adults with high-normal blood pressure (aka pre-hypertension, defined as 120-139/80-89 mmHg) have an adverse cardiometabolic risk profile.
The prevalence of high-normal blood pressure in disease-free US adults is 36.3%; it is especially common in people with overweight/obesity, enlarged waist lines, and elevated glucose, insulin, hemoglobin A1c (glycated glucose), C-reactive protein (an inflammatory marker), and triglycerides (blood fats).
High-normal blood pressure is an independent risk factor for cardiovascular disease (CVD)...[3-5]
Recent evidence strongly suggests that testosterone deficiency is a predisposing factor for various chronic illnesses, including cardiovascular disease, diabetes and osteoporosis.[1-3]Testosterone deficiency has also been implicated as a modifiable disease risk factor for various chronic diseases in otherwise well patients.[4-7]
Cardiovascular disease, diabetes and osteoporosis-related fractures consume a significant portion of the $2.3 trillion in annual U.S. health expenditures. The economic impact of diabetes is estimated at $503 billion, $152 billion for cardiovascular disease, and $6 billion for osteoporosis-related fractures.[8-10]
Thus, the total burden of these diseases is over $660 billion, representing approximately 29% of all U.S. health care expenditures in 2008. Since testosterone deficiency is a potentially modifiable risk factor for these and other medical conditions, it may be responsible for substantial financial and quality-of-life burden on the U.S. health care system.
A study was conducted to specifically quantify the cost burden imposed by consequences of testosterone deficiency ...
Your waistline not only makes or breaks your esthetic appearance; if you belly gets too large, it may greatly jeopardize your health and even longevity.
Waist circumference strongly correlates with abdominal obesity and is the most commonly used measure of body fat distribution.[1, 2] Many studies have found enlarged waist circumferences to be associated with all-cause mortality, in most cases independently of general obesity.[3-11]
Abdominal obesity (aka visceral obesity) appears to be more strongly associated with multiple chronic diseases than is gluteo-femoral obesity (fat deposition around the butt and thighs). Increased waist circumference confers a health risk even in normal weight people.
A notable large study investigated the association of waist circumference with mortality using intuitive 2 in (5 cm) increments for men and women, and also evaluated risk within narrow categories of body fatness (BMI). In addition, the study estimated years of life lost due to a large waist circumference.