Objectives: To determine if insulin-like growth factor 1 (IGF-1) and androgen levels (1) correlate with the presence and severity of acne in adult men and women, and (2) correlate directly with each other and interact in affecting acne.
Design: Case-control study and single-center examination of hormone levels in a cohort of volunteers.
Setting: Academic referral center.
Patients: Thirty-four subjects (8 women and 8 men with clinical acne, 10 women and 8 men without clinical acne). Clinical acne is defined by a history of persistent acne (acne present on most days for several years), recent acne treatment, and the presence of 10 or more inflammatory acne lesions and 15 or more comedones.
Interventions: Single visit for serum sampling.
Main outcome measures: Serum levels of IGF-1 and androgens were determined, adjusted for age, and compared based on the presence or absence of clinical acne using an analysis of covariance. Correlations between hormone levels and acne lesion counts were calculated within each subgroup. Correlations were also calculated between serum levels of IGF-1 and androgens. Further statistical testing was conducted to determine whether IGF-1 or androgens had a greater effect on acne lesion counts.
Results: Dehydroepiandrosterone (DHEAS), dihydrotestosterone (DHT), and IGF-1 correlated positively with acne lesion counts in women. Androstenedione and DHEAS correlated with acne lesion counts in men. Although the age-adjusted mean serum levels of IGF-1 were higher in women with clinical acne than in women without clinical acne, this difference did not achieve statistical significance. No difference in IGF-1 level was noted in men based on the presence of clinical acne. In women with clinical acne, IGF-1 correlated with DHT. In men with clinical acne, IGF-1 correlated with DHEAS and androstenedione. In men and women with clinical acne, the effects of androgens on increased acne lesion counts were dependent on the influence of IGF-1.
Conclusions: Increased IGF-1 levels in addition to androgens may influence acne in adult men and women. While IGF-1 appears to have a stronger effect on acne in women, androgens may play a greater role in acne for men. However, in both men and women these hormones are interrelated, possibly owing to reciprocal effects on hormone production.