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.

Impact of OATP1B1, MDR1, and CYP3A4 expression in liver and intestine on interpatient pharmacokinetic variability of atorvastatin in obese subjects.

Individual variability in expression and function of organic anion-transporting polypeptide 1B1 (OATP1B1), multidrug resistance protein 1 (MDR1), and/or cytochrome P450 3A4 (CYP3A4) may impact the clinical response of many drugs. We investigated the correlation between expression of these proteins and pharmacokinetics of atorvastatin, a substrate of all three, in 21 obese patients with paired biopsies from liver and intestinal segments. The patients were also screened for the SLCO1B1 c.521T→C variant alleles. Approximately 30% (r(2) = 0.28) of the variation in oral clearance (CL/F) of atorvastatin was explained by hepatic OATP1B1 protein expression (P = 0.041). Patients carrying the SLCO1B1 c.521C variant allele (homozygous, n = 4; heterozygous, n = 2) exhibited 45% lower CL/F of atorvastatin than the c.521TT carriers (P = 0.067). No association between hepatic and intestinal expression of MDR1 or CYP3A4 and atorvastatin pharmacokinetics was found (P > 0.149). In conclusion, this study suggests that OATP1B1 phenotype is more important than CYP3A4 and MDR1 phenotypes for the individual pharmacokinetic variability of atorvastatin.