1712. Long term antibiotic use in adolescents with acne and effect on weight
Session: Poster Abstract Session: Studies of the Interface of Host-Microbial Interaction
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
  • Long_Term_Antibiotic_Use_IDweek_Poster_09262013.pdf (346.6 kB)
  • Background: Overweight is epidemic in the U.S.  Antibiotics (ABX) increase weight in animals, perhaps by modifying gut flora. We hypothesized that a similar phenomenon might be occurring in healthy teenagers. Objective: To determine whether prolonged oral ABX in adolescents with acne affect weight.

    Methods: We conducted a retrospective cohort study using weight measurements from the past 10 years from the Palo Alto Medical Foundation in Northern California. Adolescents who were prescribed oral ABX for ≥4 weeks and had weights recorded pre- and post-ABX were included. Our primary outcome was within-individual change in weight-for age z-score (WAZ) before and after treatment.  We limited our pre-ABX WAZ measurements to18 months pre-ABX to minimize baseline measurement variability. Using the WAZ closest to the ABX courses, we then assessed differences in pre-ABX and post-ABX WAZ by paired t-test.  We also assessed the trajectory of WAZ using piecewise constant and linear mixed models.

    Results: 1116 adolescents with acne received prolonged ABX (82% tetracycline) and had at least one weight measurement pre- and post-treatment. Within individuals, the pre-ABX WAZ varied by a median of 0.26 z (IQR 0.15-0.41). The first post-ABX WAZ measurement was significantly lower than the last pre-ABX WAZ measurement (-0.036 z scores, p<0.001).  Similarly, the mean WAZ post-ABX was lower than the mean pre-ABX (-0.047 z score, p<0.001, piecewise constant model) and the slope of the WAZ change was also diminished post-ABX (-0.025, p<0.001, piecewise linear mixed model). Of the 1116 teens, 273 (25%) had a post-ABX WAZ that decreased ≥0.2 z-scores compared to their pre-ABX WAZ; the opposite (increase ≥0.2 z-scores) occurred in 187(15%) teens. Analyses limited only to tetracycline ABX gave similar results. 

    Conclusion: In this healthy population, we found no evidence that antibiotic use for acne resulted in increased weight in the following year.  Rather, we identified a statistically, though not clinically, significant, decrease in WAZ post-ABX compared to pre-ABX.   Further studies looking at different cohorts, age groups and antibiotics would provide further insight into relationships between antibiotics and weight in humans.

    Despina Contopoulos-Ioannidis, MD1,2, Catherine Ley, PhD3, Ting Ma, MS3, Cliff Olson, MBA4, Xiaoli Shi, BSc4, Harold Luft, PhD5, Trevor Hastie, PhD6 and Julie Parsonnet, MD7, (1)Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA, (2)Health Policy Research, Palo Alto Medical Foundation Research Institute, Palo Alto, CA, (3)Medicine, Stanford University School of Medicine, Stanford, CA, (4)Information Management, Palo Alto Medical Foundation Research Institute, Palo Alto, CA, (5)Palo Alto Medical Foundation Research Institute, Palo Alto Medical Foundation Research Institute, Palo Alto,, CA, (6)Department of Statistics and Biostatistics, Stanford University, Stanford, CA, (7)Medicine, Division of Geographic Medicine and Infectious Diseases, Stanford University School of Medicine, Stanford, CA


    D. Contopoulos-Ioannidis, None

    C. Ley, None

    T. Ma, None

    C. Olson, None

    X. Shi, None

    H. Luft, None

    T. Hastie, None

    J. Parsonnet, None

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