Strengths And Limitations Of Microbiome
The research methods in the studies reviewed improved in sophistication and clarity over time from 2011 to 2016. Three of the studies determined that antibiotics resulted in a risk for increased BMI in boys but not in girls (Ajslev et al., 2011; Azad et al., 2014; Murphy, et al., 2014). In general, repeated exposures to antibiotics (Saari et al., 2015; Schwartz et al., 2016; Scott et al., 2016) or broad-spectrum antibiotics (Bailey et al., 2014), in particular macrolides (Saari et al., 2015), were found to be associated with an increase in BMI.
Strengths and Limitations
Most of the research reviewed controlled for potential confounders on the effect of antibiotics on BMI: mode of delivery, maternal pre-pregnancy weight, maternal smoking, maternal diabetes, birth weight, socioeconomic status, and steroid use. However, the indirect assessment of prescription and BMI data in the earlier studies, i.e. parent report, introduces a possibility of recall bias. Direct measurements and electronic access of prescription records increases data validity. In this regard, the more recently published studies have greater validity than earlier studies as the methodologies have been refined. Broad-spectrum antibiotics and macrolides were implicated more often than narrow-spectrum antibiotics in BMI increase, but the lack of consistent category definitions across the studies limits application of this finding. Recording specific antibiotic classes from health records, as in…