• Sunscreens block the absorption of the sunlight spectrum responsible for the cutaneous synthesis of vitamin D (ultraviolet B). The present study was prompted by our observation of suppression of cutaneous vitamin D formation by a single application of sunscreening agents. We measured the index of vitamin D body store, serum 25-hydroxyvitamin D (25-OH-D) level, in 20 long-term users of p-aminobenzoic acid (PABA) and in 20 controls matched by age and exposure to sunlight. Serum 25-OH-D levels were significantly lower among long-term PABA users than among normal controls: 40.2 ± 3.2 vs 91.3 ± 6.2 nmol/L. Furthermore, vitamin D deficiency, ie, 25-OH-D levels below 20.0 nmol/L, was seen in two PABA users and in none of the controls. This preliminary study suggests that long-term use of PABA may be associated with low body stores of vitamin D in some persons.
(Arch Dermatol 1988;124:1802-1804)
Matsuoka LY, Wortsman J, Hanifan N, Holick MF. Chronic Sunscreen Use Decreases Circulating Concentrations of 25-Hydroxyvitamin DA Preliminary Study. Arch Dermatol. 1988;124(12):1802-1804. doi:10.1001/archderm.1988.01670120018003