Lactase Persistence, Milk Intake, and Adult Acne: A Mendelian Randomization Study of 20,416 Danish Adults.

Whether there is a causal relationship between milk intake and acne is unknown. We tested the hypothesis that genetically determined milk intake is associated with acne in adults using a Mendelian randomization design. LCT-13910 C/T (rs4988235) is associated with lactase persistence (TT/TC) in Northern Europeans. We investigated the association between milk intake, LCT-13910 C/T (rs4988235), and acne in 20,416 adults (age-range: 20⁻96) from The Danish General Suburban Population Study (GESUS). The adjusted observational odds ratio for acne in any milk intake vs. no milk intake was 0.93(95% confidence interval: 0.48⁻1.78) in females and 0.49(0.22⁻1.08) in males aged 20⁻39 years, and 1.15(95% confidence interval: 0.66⁻1.99) in females and 1.02(0.61⁻1.72) in males above 40 years. The unadjusted odds ratio for acne in TT+TC vs. CC was 0.84(0.43⁻1.62) in the age group 20⁻39 years, and 0.99(0.52⁻1.88) above 40 years. We did not find any observational or genetic association between milk intake and acne in our population of adults.