Genetic Variants and Lifestyle Factors in Androgenetic Alopecia Patients: A Case-Control Study of Single Nucleotide Polymorphisms and Their Contribution to Baldness Risk

Single nucleotide polymorphisms (SNPs) found to be associated with Androgenetic Alopecia (AGA) to date, are characterized by an apparent reduced penetrance into the phenotype suggesting a role of other factors in the etiology of AGA. Objective: We conducted a study to investigate the role of specific allelic variants in AGA controlling for nutritional and lifestyle factors. Methods: Individual patterns of SNPs present in the baldness susceptibility locus at 20p11 (rs1160312 and rs6113491) or close to the androgen receptor (AR) gene in chromosome X (rs1041668) were investigated in 212 male subjects. Information on socio-demographic characteristics, medical history, smoking, and diet was also collected. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: After controlling for age, diet, BMI, family history of AGA, and smoking, an increased risk of AGA was found for subjects with [A] alleles for both rs1160312 (OR: 2.97; 95% CI: 1.34-6.62) and rs6113491 (OR: 2.99; 95% CI: 1.37-6.52), and for subjects with the TT genotype for rs1041668 (OR: 4.47; 95% CI: 1.60-12.5). Multivariate logistic regression indicates that diet, familiarity, and BMI, but not smoking, remain statistically significant despite the different SNP genotypes. Conclusions: To our knowledge, this is the first indication that the rs1160312, rs6113491, and rs1041668 polymorphisms are independent risk factors for AGA that can be modulated by diet.