Acne and dairy products in adolescence: results from a Norwegian longitudinal study.

BACKGROUND: Acne is a very common skin condition, and it is of great interest to elucidate lifestyle factors that may contribute to its occurrence. In the last decade, the acne-diet connection has been brought back to credibility.

OBJECTIVE: To examine whether high intakes of dairy products in early adolescence is associated with moderate to severe acne in later adolescence.

METHODS: The study is a longitudinal, questionnaire-based population study of Norwegian adolescents. Students attending the 10th grade (15-16 years old) of compulsory schooling in Oslo in 2000-2001 and the 13th grade (18-19 years old) 3 years later, in 2004, were invited. Dairy product consumption was self-reported at age 15-16 and acne severity was self-assessed and reported at age 18-19.

RESULTS: The overall prevalence of moderate to severe acne was 13.9%. High intakes (≥2 glasses per day) of full-fat dairy products were associated with moderate to severe acne. In boys with exclusively high intakes of full-fat dairy products, the odds ratio for acne was 4.81 (1.59-14.56). A high total intake of dairy products was associated with acne in girls (OR 1.80, 1.02-3.16). No significant associations were found between acne and intake of semi-skimmed or skimmed dairy products, and not with moderate intakes of any fat variety of dairy products.

CONCLUSION: This study shows association between high intakes of dairy products and acne in adolescence. Our findings support a hypothesis suggesting that dairy consumption may be a factor contributing to acne. The study is based on multiple hypothesis testing, and the methodological limitations must be considered when interpreting the results.