visit was one, with finasteride (48.1%) being most common. There were 20 (15.3%) patients with abnormal lab results: three (3.1%) with abnormal TSH, seven (6.8%) with abnormal vitamin D, four (3.8%) with abnormal zinc, and eight (6.5%) with abnormal ferritin. Two patients had more than one abnormal result.
Forty-two (32%) patients received supplementation. While NYU laboratory guidelines were used to define patients with low ferritin and vitamin D, patients were supplemented at <40 ng/mL and <30 ng/mL, respectively. Patients were started on supplements immediately after finding abnormal lab results and received supplements that specifically addressed their vitamin or hormone deficiency. Our results showed no statistically significant difference in hair measurements at baseline or follow-up between supplemented and nonsupplemented patients (Table 2). There was no significant difference in the change in hair density and diameter between groups. Multivariate regression analysis confirmed that supplementation did not significantly impact hair density or diameter (P=0.73; P=0.96, respectively). Baseline hair density and diameter were positively associated with change in hair density and diameter, respectively (standardized coefficient [β] 0.57, P<0.01; β 0.61, P<0.01). The number of prescribed oral medications was negatively associated with change in hair diameter (β -6.60; P=0.04). It is likely that patients on a higher number of oral medications had more severe non scarring alopecia and thus were more likely to have poorer response compared to those with milder hair loss at initial presentation.
Our findings suggest that laboratory testing may not be useful for the management and treatment of non-scarring alopecia. The prevalence of abnormal TSH, vitamin D, and zinc levels in our cohort was lower than the prevalence amongst the general adult population.3-5 Supplementation was also not associated with increased hair density or diameter, therefore supplements – although important for optimal nutrition – may not lead to improved outcomes in androgenetic alopecia or telogen effluvium. Finally, we found that factors beyond supplementation, such as baseline hair parameters and the number of prescribed oral medications, may serve as better predictors of hair growth.
