Examining the Role of Socioeconomic Factors, Birth Defects in Child Mortality
Two birth cohorts — one from England and one from Sweden — were assessed to determine adverse characteristics and socioeconomic factors leading to infant or child mortality.
Adverse birth characteristics and socioeconomic factors such as low birthweight, prematurity, maternal age, and congenital anomalies are associated with the substantially higher rates of child mortality in England compared with Sweden, according to a comparative analysis published in the Lancet.
Using live birth records from the Hospital Episode Statistics in England and the Medical Birth Register in Sweden, investigators crafted nationally representative cohorts of singleton live births that were linked with hospital admission and mortality data. Children were followed to their fifth birthday or death, whichever occurred first. The primary outcome was comprised of all-cause mortality at age 2 to 27 days, 28 to 364 days, and 1 to 4 years, with comparisons made between England and Sweden. In the analysis, investigators adjusted for gestational age, birthweight, sex, and congenital anomalies (ie, birth characteristics) as well as for maternal age and socioeconomic status (ie, socioeconomic factors).
A total of 3,932,886 births and 11,392 deaths were reported in the English cohort compared with 1,013,360 births and 1927 deaths in the Swedish cohort. Often, children born in England were born at earlier gestational ages and weighed less compared with children born in Sweden. Unadjusted mortality was higher in England, represented by approximately 607 more deaths per year at age 2 days to 4 years.
Additionally, the unadjusted mortality rate was highest for children born at gestational ages 24 to 27 weeks, children with a birthweight of 500 to 1499 grams, and children born with congenital anomalies. The unadjusted hazard ratio for England vs Sweden was 1.66 (95% CI, 1.53-1.81), and the final adjusted hazard ratio was 1.13 (95% CI, 1.04-1.23). In the adjusted analysis, the highest mortality risk at 2 to 27 days was consistently associated with a birthweight <1500 grams, gestational age <28 weeks, and congenital anomalies. Approximately 68% and 11% of the excess mortality risk in England compared with Sweden was attributable to birth characteristics and socioeconomic factors, respectively.
A limitation of this analysis includes the use of various measurements for socioeconomic status in the 2 countries, which may have led to inconsistent findings.
The investigators suggest initiatives aimed at reducing child mortality “in England relative to Sweden could be achieved through universal programmes to improve the health of women and reduce health inequalities before and during pregnancy.”
Zylbersztejn A, Gilbert R, Hjern A, Wijlaars L, Hardelid P. Child mortality in England compared with Sweden: a birth cohort study [published online May 3, 2018]. Lancet. doi:10.1016/S0140-6736(18)30670-6