Does degree of baldness influence vitamin D status?

Objective: To determine the association, if any, between male-pattern hair loss (baldness) and serum 25-hydroxyvitamin D (25-OHD) levels.
Design and Participants: A cross-sectional study of 296 healthy middle-aged and older men.
Main Outcome Measures: Degree of baldness was independently assessed by two researchers using the Hamilton-Norwood scale and serum 25-OHD was measured in all men.
Results: Classification of the degree of baldness by the two researchers showed a high level of agreement (kappa = 0.93). Forty-eight per cent of men had no hair loss or mild frontotemporal recession, 15% had predominant vertex loss, and 37% had significant scalp and vertex loss. After data were adjusted for potential confounding factors - including age, month of 25-OHD measurement, exercise levels, use of sunscreen, skin type and frequency of outdoor hat wearing - no significant differences in 25-OHD levels between these groups was detected (P = 0.60).
Conclusions: The degree of baldness does not appear to influence serum 25-OHD levels. The high prevalence of baldness in older men does not explain sex differences in 25-OHD levels. Other novel hypotheses are required to help determine whether baldness serves any physiological purpose.