https://www.selleckchem.com/products/tp-1454.html 81; 95% CI, 0.71-0.93). For children without any siblings, only the prosocial behavior scale was significantly associated with pet ownership (OR, 0.21; 95% CI, 0.07-0.66). In longitudinal models, cat-only and dog-only groups were associated with fewer emotional symptoms and peer problems compared with non-pet owners. CONCLUSIONS Early school age is an important period for family pet acquisition. Pets may protect children from developing social-emotional problems and should be taken into account when assessing child development and school readiness. Children without siblings may benefit most in terms of their prosocial behavior. OBJECTIVE To determine how gestational age relates to research-identified autism spectrum disorder (ASD-R) in the context of perinatal risk factors. STUDY DESIGN This is a population-based cohort study using the 1994-2000 Olmsted County Birth Cohort. Children included were born and remained in Olmsted County after age 3 years. ASD-R status was determined from signs and symptoms abstracted from medical and educational records. Cox proportional hazards models were fit to identify associations between perinatal characteristics and ASD-R. RESULTS The incidence of preterm birth ( less then 37 weeks' gestation) was 8.6% among 7876 children. The cumulative incidence of ASD-R was 3.8% (95% CI 3.3-4.2) at 21 years of age. Compared with children born at full term, the risk of ASD-R appeared to be increased for children born preterm with unadjusted hazard ratios (HRs) of 2.62 (95% CI 0.65-10.57), 1.68 (95% CI 0.54-5.29), and 1.60 (95% CI 1.06-2.40) for children born extremely preterm, very preterm, and moderate-to-late preterm, respectively. In a multivariable model adjusted for perinatal characteristics, the associations were attenuated with adjusted HRs of 1.75 (95% CI 0.41-7.40), 1.24 (95% CI 0.38-4.01), and 1.42 (95% CI 0.93-2.15), for children born extremely preterm, very preterm, and moderate-to-la