Red Hair and Rh- Blood go Hand-in-Hand

Health Status by Gender, Hair Color, and Eye Color: Red-Haired Women are the Most Divergent with the Lowest Viability and the Highest Fertility

Abstract

Background Red hair is associated with pain sensitivity, and more so in women than in men. Hair redness may thus interact with a female-specific factor. We tested this hypothesis on a large sample of Czech and Slovak respondents. They were asked about the natural redness and darkness of their hair, their natural eye color, their physical and mental health (24 categories), and other personal attributes (height, weight, number of children, lifelong number of sexual partners, frequency of smoking).

Results We found that red-haired women did worse than other women in ten health categories and better in only three. In particular, they were more prone to colorectal, cervical, uterine, and ovarian cancer. Cancer risk increased steadily with increasing hair redness except for the reddest shade. Red-haired men showed a balanced pattern of health effects, doing better than other men in three categories and worse in three. Number of children was the only category where both male and female redheads did better than other respondents. We also confirmed earlier findings that red hair is naturally more frequent in women than in men.

Conclusion Red-haired women had higher fecundity and sexual attractiveness, but this selective advantage seems offset by worse health outcomes and therefore lower viability. The resulting equilibrium between these two counterbalancing forces might explain why red hair has remained less common than other hair and eye colors. Of the ‘new’ hair and eye colors, red hair diverges the most from the ancestral state of black hair and brown eyes. It is the most sexually dimorphic variant, not only in population frequency but also in health outcomes. This sexual dimorphism seems to have resulted from a selection pressure that acted primarily on early European women and which led to a general and apparently rapid diversification of hair and eye colors.

Worse Health Status and Higher Incidence of Health Disorders in Rhesus Negative Subjects

Rhesus negative subjects reported to have more frequent allergic, digestive, heart, hematological, immunity, mental health, and neurological problems.

The RhD negative subjects expressed many indices of a worse health status. Men, women or both sexes reported more frequent allergic, digestive, heart, hematological, immunity, mental health and neurological problems. They also reported the usage of more drugs prescribed by doctors per day, attended more specialized doctors, namely, dermatologists, gynecologists, internal medicine doctors, neurologists, and psychiatrists (men) in the past two years, a higher frequency of headaches and being tired more often than RhD positive subjects. Incidence of various diseases and disorders also differed between RhD negative and RhD positive subjects, mostly being higher in the former.

RhD negative subjects have increased the risk of developing of certain heart diseases, respiratory diseases and some immunity and autoimmunity related diseases, for example rheumatoid arthritis. The general pattern suggests that RhD negative subjects could have problems with autoimmunity, could be more resistant to infections of viral origin and could be less resistant to infections of bacterial origin

RhD negative men more often reported certain mental health disorders including panic disorders, antisocial personality disorders and attention deficits, ticks, fasciculation, thyroiditis, immunity disorders, allergies, especially skin allergies, excessive bleedings, anemia, osteoporosis, liver disease, infectious diseases and acute diarrhea diseases, while they less often reported gall bladder attacks, coeliac disease, maldigestion, malabsobtion, warts, some types of cancers and prostate hypertrophy.

RhD negative women reported more frequently psoriasis, constipation and diarrheas, ischemic diseases, type 2 diabetes, some types of cancers, lymphatic nodes swelling, vitamin B deficiency, thrombosis, tonsil stones, too high sex desire, precocious puberty, urinary tract infections, scoliosis and they less often reported hearing loss, weight loss, hypoglycemia, glaucoma, fasciculation and warts.

Are rh negative people more likely to have red hair and/or freckles?