biostudies-literatureContopoulos-Ioannidis DGNICHD NIH HHSEunice Kennedy Shriver National Institute of Child Health &amp; Human DevelopmentNational Institutes of Health1098-105https://www.ebi.ac.uk/biostudies/studies/S-EPMC4790625biostudies-literatureUnknown71(4)<h4>Objectives</h4>Antibiotics increase weight in farm animals and may cause weight gain in humans. We used electronic health records from a large primary care organization to determine the effect of antibiotics on weight and BMI in healthy adolescents with acne.<h4>Methods</h4>We performed a retrospective cohort study of adolescents with acne prescribed ≥4 weeks of oral antibiotics with weight measurements within 18 months pre-antibiotics and 12 months post-antibiotics. We compared within-individual changes in weight-for-age Z-scores (WAZs) and BMI-for-age Z-scores (BMIZs). We used: (i) paired t-tests to analyse changes between the last pre-antibiotics versus the first post-antibiotic measurements; (ii) piecewise-constant-mixed models to capture changes between mean measurements pre- versThe Journal of antimicrobial chemotherapyEffect of long-term antibiotic use on weight in adolescents with acne.PMC4790625R01 HD063142R03HD072400Contopoulos-Ioannidis DGParsonnet JLuft HSOlson CHastie TWang WMa TLey CShi XfalseEffect of long-term antibiotic use on weight in adolescents with acne.<h4>Objectives</h4>Antibiotics increase weight in farm animals and may cause weight gain in humans. We used electronic health records from a large primary care organization to determine the effect of antibiotics on weight and BMI in healthy adolescents with acne.<h4>Methods</h4>We performed a retrospective cohort study of adolescents with acne prescribed ≥4 weeks of oral antibiotics with weight measurements within 18 months pre-antibiotics and 12 months post-antibiotics. We compared within-individual changes in weight-for-age Z-scores (WAZs) and BMI-for-age Z-scores (BMIZs). We used: (i) paired t-tests to analyse changes between the last pre-antibiotics versus the first post-antibiotic measurements; (ii) piecewise-constant-mixed models to capture changes between mean measurements pre- vers2016-01-01T00:00:00Z2016 Apr2025-04-26T09:16:57.454Z2019-03-27T02:11:02ZS-EPMC47906252678277310.1093/jac/dkv455