Results: Classification of the degree of baldness by the two researchers showed a high level of agreement (κ = 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.
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