A significantly lower frequency of acne, as well as lower rates of severe acne, has been reported among lactose-intolerant patients from the midwestern United States, according to the results of a retrospective, cross-sectional analysis that was published in the Journal of the European Academy of Dermatology and Venereology.
Investigators sought to evaluate the frequency of acne in a large, lactose-intolerant US patient population compared with a non-lactose-intolerant population to offer additional insight into the possible relationship between dairy consumption and acne. The Northwestern Medicine Enterprise Data Warehouse (NMEDW), a medical record data repository of more than 6 million patients, was used to obtain data for all patients 18 to 89 years of age with a diagnosis of lactose intolerance and/or acne between January 2001 and November 2017. In patients with acne, systemic therapy (ie, isotretinoin and the major tetracycline moieties [tetracycline, doxycycline, and minocycline]) vs no systemic therapy was used to categorize the severity of a patient’s acne.
Of a total of 2970 patients with lactose intolerance, 7.7% had a diagnosis of acne, yielding a statistically significantly lower occurrence of acne than seen in the 272,125 patients without lactose intolerance, among whom 15.2% had a diagnosis of acne (adjusted odds ratio 0.56; 95% CI, 0.49-0.65; P <.0001). Of note, among all 41,637 patients with acne, severe acne was significantly less common among the lactose-intolerant group with acne compared with the non-lactose-intolerant group with acne (adjusted odds ratio 0.51; 95% CI, 0.31-0.82; P =.007).
Major limitations of the study include the inability to validate documentation of data and diagnostic coding beyond what was included in the original NMEDW medical record data entry. Moreover, possible confounding data, including age at menarche and baseline dietary analysis, were not obtained. Because of the cross-sectional design of the study, there was a lack of temporality between lactose intolerance and acne. Because the researchers were unable to establish a causal relationship, the association reported in this study is therefore a measure of prevalence, not of incidence.
The investigators concluded that the findings from this study contribute to the limited existing literature on dairy and acne. This study is the first to use physician-designated diagnostic coding for lactose intolerance as a measure of dairy exposure. Additional research is warranted to explore the role played by insulin growth factor 1 and the potential association between acne and dairy intake.
Orrell KA, Kelm RC, Murphrey M, et al. Frequency of acne in lactose intolerant adults: A retrospective cross-sectional analysis within a large Midwestern US patient population [published online January 21, 2019]. J Eur Acad Dermatol Venereol. doi: 10.1111/jdv.15441