Change in prevalence of chronic conditions between childhood and adolescence among extremely low-birth-weight children.

CONTEXT: Extremely low-birth-weight (ELBW) children have high rates of chronic conditions during childhood. Information on their trajectory of health during adolescence is needed for health care planning.
OBJECTIVE: To examine changes in the rates of chronic conditions between the ages of 8 and 14 years among ELBW children compared with normal-birth-weight (NBW) controls. DESIGN, SETTING, AND PARTICIPANTS: Cohort study conducted from 2004 through 2009 of 181 ELBW children (weight < 1 kg) and 115 NBW controls of similar sociodemographic status born from 1992 through 1995 in Cleveland, Ohio. MAIN OUTCOME MEASURES: Rates of chronic conditions overall (measured with the revised Questionnaire for Identifying Children With Chronic Conditions) and rates of asthma and obesity.
RESULTS: The overall rates of chronic conditions did not change significantly between the ages of 8 and 14 years among ELBW children (75% at age 8 years vs 74% at age 14 years) or NBW controls (37% at age 8 years vs 47% at age 14 years). In generalized estimating equations logistic regression adjusting for sociodemographic status, sex, and race, ELBW children continued to have a higher rate of chronic conditions than NBW controls at age 14 years (74% vs 47%, respectively, adjusted odds ratio [AOR], 2.8 [95% confidence interval {CI}, 1.7 to 4.6]). Rates of asthma requiring medication did not change between the ages of 8 and 14 years among ELBW children (23% at both ages) but increased among NBW controls from 8% at age 8 years to 17% at age 14 years (P = .002). Differences in rates of asthma between ELBW and NBW children were no longer significant at the age of 14 years (23% vs 17%, respectively; AOR, 1.5 [95% CI, 0.8 to 2.8]). Mean z scores for body mass index increased in ELBW children from 0.06 at age 8 years to 0.38 at age 14 years (P <.001) and rates of obesity increased from 12% at age 8 years to 19% at age 14 years (P = .02). However, the scores and rates did not change among NBW controls such that at the age of 14 years the differences between ELBW and NBW children in mean z scores for body mass index (0.38 vs 0.56, respectively; adjusted mean difference -0.2 [95% CI, -0.5 to 0.1]) or rates of obesity (19% vs 20%, respectively; AOR, 1.1 [95% CI, 0.6 to 2.0]) were not significant.
CONCLUSIONS: Among ELBW children, rates of overall chronic conditions and asthma did not change between the ages of 8 and 14 years but the rate of obesity increased. Compared with NBW controls, the rates of chronic conditions were higher but there were no significant differences in the rates of asthma or obesity.