Association of schizophrenia with low maternal body mass index, small size at birth, and thinness during childhood.

Background: Nutritional factors in early life may contribute to the neurodevelopmental deficit in schizophrenia. This study explores the influence of maternal body size, size at birth, and childhood growth on future risk for schizophrenia.
Subjects and Methods: This population-based cohort study comprised births at Helsinki University Central Hospital in Helsinki, Finland, from 1924 to 1933. Prospective data from birth and school health records of 7086 individuals were collected and linked to the Finnish Hospital Discharge Register.
Results: Schizophrenia or schizoaffective disorder had been diagnosed in 114 individuals. A lower late-pregnancy maternal body mass index (BMI) increased the risk (odds ratio [OR], 1.09 per kilogram/meter(2); 95% confidence interval [CI], 1.02-1.17) for schizophrenia among the offspring. The risk of schizophrenia increased with low birth weight (OR, 1.48 per kilogram; 95% CI, 1.03-2.13), shortness at birth (OR, 1.12 per centimeter; 95% CI, 1.03-1.22), and low placental weight (OR, 1.22 per 100 g; 95% CI, 1.04-1.43). Schizophrenia cases were thinner than comparison subjects from 7 to 15 years of age. In a joint model comprising late-pregnancy maternal BMI, body size at birth, and childhood BMI, childhood BMI was an independent predictor of schizophrenia, whereas other factors exhibited attenuated effects.
Conclusion: Indicators of intrauterine and childhood undernutrition are associated with an increased lifetime risk of schizophrenia.