Born Small for Gestational Age Impact of Linear Catch-up Growth

Sammanfattning: The purposes of the thesis were to study associations between size at birth, short adult stature and risks of subnormal intellectual performance, high blood pressure, and overweight among males, and to study associations between size at birth, short adult stature and risk of overweight and giving birth to small for gestational age (SGA) infants among females.The effect of short adult stature on intellectual performance among males was analyzed in two population-based cohort studies. Data were obtained from the Swedish Birth Register which was individually linked to the Swedish Conscript Register. Being born SGA was associated with increased risks of subnormal intellectual performance in all four dimensions included in the test, and lack of catch-up growth leading to short adult stature further increased this risk. If anything, logical performance was found to be most affected.To estimate the risk of high blood pressure in males born SGA we used the Birth Register linked to the Conscript Register. Being born SGA was associated with a slightly increased risk of high systolic blood pressure, and being born light and ending up with short adult stature further increased this risk.Association between short adult stature and overweight was analyzed in both males and females born SGA, in two different studies. In the male cohort data from the Birth Register was linked to the Conscript Register. In females the Birth Register was used twice, when the females were born and when they gave birth to their first child. In both the male and female cohort, there was an increased risk of becoming overweight among those born SGA who also ended up with short adult stature.Finally, an intergeneration study was performed using the Birth Register to analyze associations between being born short for gestational age and giving birth to short infants. Catch-up growth to normal adult stature among women born short-for-gestational age was associated with reduced risk of giving birth to a short-for-gestational age infant.Conclusions. Among males born SGA, short adult stature is associated with increased risk of subnormal intellectual performance, high blood pressure and overweight compared to those with normal adult stature. Similarly, among females born SGA, there is an increased risk of becoming overweight in those with short adult stature, compared with those not short as adult. Females born short for gestational age, with short adult stature are at increased risk of giving birth to a short infant.