Socioeconomic Inequality In Birth Weight, Low Birth Weight, And Small For Gestational Age Has Increased In Denmark From 1981 To 2001
Mortensen, LH; Olsen, EM; Andersen, AM
Birth weight is associated with health in infancy and later in life. Socioeconomic inequality in birth weight is an important marker of current and future population health inequality. Our objective was to examine the effect of maternal education on birth weight, low birth weight (LBW, birth weight and lt;2,500 g), and small for gestational age (SGA) in Denmark 1981 to 2001. Data on 1,314,276 singleton live births 1981 and #150;2001, and highest completed maternal education in the year preceding birth was obtained from national registries. The mean birth weight increased from 3403 g in 1981 to 3534 g in 2001, while the prevalence of LBW and SGA decreased from 4.2% to 2.9%, and 5.9% to 4.1%, respectively. The relative index of inequality (RII) increased for all outcomes from 1981 to 2001 (Birth weight from 97.7 g (95% Confidence Interval 88.4 g, 107.1 g) to 314.4 g (305.7 g, 323.1 g), LBW from an odds ratio of 1.88 (1.72,2.06) to 3.56 (3.21,3.94), and SGA from an odds ratio of 1.72 (1.60,1.86) to 3.38 (3.11,3.69), respectively). In conclusion, our results show a substantial increase in the socioeconomic inequality in birth weight, LBW, and SGA in Denmark from 1981 to 2001.