The figure shows the means and the distribution computed as the kernel probability density for male and female heterozygotes (het), Rh-positive homozygotes (hom), and Rh-negative homozygotes (neg).
Post hoc ANCOVA tests with physical health problems score as the dependent variable performed separately for women and men showed significantly worse health in Rh-positive female homozygotes than Rh-negative female homozygotes (p = 0.026, eta2 = 0.053, beta = -0.225) and Rh-positive female heterozygotes (p = 0.047, eta2 = 0.030, beta = 0.170). No other difference between Rh genotypes was significant either for physical or mental health problems score.
To see which specific health problems were responsible for the observed effect of the Rh genotype, we performed a partial Kendall correlation test controlled for age for all source variables originally used for computing physical and mental health problems scores. Table 2 shows that, generally, heterozygotes have better health than Rh-positive homozygotes. In women, Rh-negative homozygotes had better health than Rh-positive homozygotes and often also than heterozygotes while the opposite is true for men. However, the general pattern also had some exceptions. For example, heterozygotic men scored better in most parameters of physical and mental health than Rh-positive homozygotes but they reported suffering from more chronic problems and consuming more medical drugs currently.
To be able to compare our results with those already published, we pooled Rh-positive homozygotes and heterozygotes and repeated the analyses with the binary variable Rh-positivity instead of nominal variable Rh genotype (Fig. 2). ANCOVA tests showed no significant effect of Rh phenotype or Rh phenotype-sex interaction on the scores of mental or physical health problems (physical health-sex-Rh: p = 0.103, eta2 = 0.010; mental health-sex-Rh phenotype: p = 0.912, eta2 < 0.0001). However, partial Kendall analyses showed several significant effects of Rh phenotype on the source of physical and mental health-related variables. Generally, Rh-positive women reported worse and Rh-positive men better health than their Rh-negative peers (Table 2).
Tab. 2 . Effects of Rh genotype and phenotype on physical and mental health problems scores and their source variables