In the three cohort studies, the adjusted risk of coronary heart disease was 32% higher among individuals with severe vertex baldness compared with men with full hair.
|English: The back of a middle-aged American man's head, showing typical male pattern baldness (Photo credit: Wikipedia)|
In the case-control studies, the risk of coronary heart disease was 70% higher among bald subjects compared with those without baldness.
Hamilton-Norwood scale, which is the most commonly used classification of pattern baldness worldwide, the relationship between coronary heart disease and baldness was shown to be dependent on the severity of baldness.
The reason for the association between vertex baldness and coronary heart disease is not known. The current working hypothesis is that insulin resistance can impair the supply of nutrients to the hair follicles or a proinflammatory state could increase the inflammatory cytokines in the hair follicles.
Testosterone is the most potent androgen, and it does make the man. It’s responsible for the deep voice, increased muscle mass, and strong bones that characterize the gender, and it also stimulates the production of red blood cells by the bone marrow.
Finally, testosterone also acts on the liver. Normal amounts are harmless, but high doses can cause liver disease and boost the production of LDL (“bad”) cholesterol while lowering the amount of HDL (“good”) cholesterol.
Sex hormone binding globulin (SHBG) is a glycoprotein possessing high affinity binding for 17 beta-hydroxysteriod hormones such as testosterone and oestradiol. It is probably synthesized in the liver, plasma concentrations being regulated by, amongst other things, androgen/oestrogen balance, thyroid hormones, insulin and dietary factors, it is involved in transport of sex steroids in plasma.
Obesity is associated with increased insulin resistance. Increased insulin resistance can cause decrease in level of serum androgen binding globulin (SABG). That may also cause increased level of insulin and Insulin like growth factor (IGF-I).
Decrease level of SABG may make available more testosterone in the circulation (Free Testosterone) thereby more 5HT; as normally testosterone remains bound to SABG.
Male pattern baldness (Vertex Baldness) is due to increase activity of 5 Dihydroxy-Testosterone (5DHT or 5HT) and increase in 5HT receptor gene expression. 5HT is produced from testosterone by action of enzyme 5 alpha reductase (5ARD).
DHT also stimulates the growth of prostate cells, producing normal growth in adolescence but contributing to benign prostatic hyperplasia (BPH) in many older men.
They found that men with bald spots at the top of their heads (vertex baldness) were one and a half times more likely to have prostate cancer than those without bald spots.
The association was particularly strong for men who were diagnosed with high-grade prostate cancer at 60–69 years of age. In contrast, there was no link between a receding hairline (frontal baldness) and cancer.
The increase in level of 5 DHT, decrease in level of SABG, insulin resistance and obesity; which work towards male pattern baldness may also be responsible for increased cardiovascular risk and prostate cancer.