title: The effect of small class sizes on mortality through age 29 years: evidence from a multicenter randomized controlled trial.
abstract: Limiting the number of students per classroom in the early years has been shown to improve educational outcomes. Improved education is, in turn, hypothesized to improve health. The authors examined whether smaller class sizes affect mortality through age 29 years and whether cognitive factors play a role. They used data from the Project Student Teacher Achievement Ratio, a 4-year multicenter randomized controlled trial of reduced class sizes in Tennessee involving 11,601 students between 1985 and 1989. Children randomized to small classes (13-17 students) experienced improved measures of cognition and academic performance relative to those assigned to regular classes (22-25 students). As expected, these cognitive measures were significantly inversely associated with mortality rates (P < 0.05). However, through age 29 years, students randomized to small class size nevertheless experienced higher mortality rates than those randomized to regular size classes (hazard ratio (HR) = 1.58, 95% confidence interval (CI): 1.07, 2.32). The groups at risk included males (HR = 1.73, 95% CI: 1.05, 2.85), whites/Asians (HR = 1.68, 95% CI: 1.04, 2.72), and higher income students (HR = 2.20, 95% CI: 1.06, 4.57). The authors speculate that small classes might produce behavior changes that increase mortality through young adulthood that are stronger than the protective effects of enhanced cognition.
authors.affiliation: Mailman School of Public Health, Columbia University, New York, New York 10032, USA. pm124@columbia.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Muennig
authors.forename: Gretchen
authors.initials: G
authors.lastname: Johnson
authors.forename: Elizabeth Ty
authors.initials: ET
authors.lastname: Wilde
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D003071:Cognition; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D012307:Risk Factors; D012574:Schools / Q000458:organization & administration*; D012737:Sex Factors; D012959:Socioeconomic Factors; D013714:Tennessee; D055815:Young Adult