The cumulative prevalence of allergic diseases and asthma has risen over the past several decades. In particular, food allergy has exhibited a particularly brisk rise in children.^1-4 Furthermore, studies in the United States and other countries have demonstrated increases in allergic rhinoconjunctivitis, asthma, skin prick test positivity to common allergens, and hospitalizations due to anaphylaxis.^5-9

Objective Gut microbiota alterations are associated with obesity. Early exposure to medications, including acid suppressants and antibiotics, can alter gut biota and may increase the likelihood of developing obesity. We investigated the association of antibiotic, histamine-2 receptor antagonist (H2RA) and proton pump inhibitor (PPI) prescriptions during early childhood with a diagnosis of obesity. Design We performed a cohort study of US Department of Defense TRICARE beneficiaries born from October 2006 to September 2013. Exposures were defined as having any dispensed prescription for antibiotic, H2RA or PPI medications in the first 2 years of life. A single event analysis of obesity was performed using Cox proportional hazards regression. Results 333 353 children met inclusion criteria, with 241 502 (72.4%) children prescribed an antibiotic, 39 488 (11.8%) an H2RA and 11 089 (3.3%) a PPI. Antibiotic prescriptions were associated with obesity (HR 1.26; 95% CI 1.23 to 1.28). This association persisted regardless of antibiotic class and strengthened with each additional class of antibiotic prescribed. H2RA and PPI prescriptions were also associated with obesity, with a stronger association for each 30-day supply prescribed. The HR increased commensurately with exposure to each additional medication group prescribed. Conclusions Antibiotics, acid suppressants and the combination of multiple medications in the first 2 years of life are associated with a diagnosis of childhood obesity. Microbiota-altering medications administered in early childhood may influence weight gain.

Purpose: While gender dysphoria (GD) and autism spectrum disorder (ASD) are generally identified in isolation, research on gender-referred or person-centered language (individuals who are gender-referred or have autism suggests) individuals suggests a possible overrepresentation of ASD in persons with GD and GD in persons with ASD. We investigated diagnosed GD in patients formally diagnosed with ASD and matched controls in the Military Health System. Methods: We performed a retrospective case-cohort study of GD diagnoses in children aged 2–18 years with and without ASD utilizing health care records from 2000 to 2013. Cases were formally diagnosed with ASD and matched to five controls by date of birth, gender marker, and enrollment time. Outpatient visits for GD were identified by relevant International Classification of Diseases, Ninth Revision codes. Logistic regression analysis determined odds ratios (ORs) and 95% confidence intervals (95% CIs) of GD diagnoses by ASD. Results: A total of 48,762 children with diagnosed ASD were identified, and each matched to five controls, for a total of 292,572 children. Cases and controls were each 80% assigned male at birth. The median end age of included children was 11.6 years. Of included children, 66 (0.02%) had diagnosed GD. Children with ASD were over four times as likely to be diagnosed with a condition indicating GD (OR 4.38 [95% CI 2.64–7.27], p < 0.001) compared with matched controls. Conclusion: This study corroborates previous research indicating an overrepresentation of GD in children with ASD. Further research is needed to understand the association and to demonstrate approaches to providing optimal care to these children.