Parental Socioeconomic Status and Weight Faltering in Infants in Japan

Area of Science:

• Pediatric Health
• Socioeconomic Determinants of Health
• Public Health Research

Background:

• Previous UK and Danish studies found no link between low socioeconomic status (SES) and weight faltering.
• Limited research exists on this association in other developed nations.
• This study addresses the gap by examining SES and infant weight faltering in Japan.

Purpose of the Study:

• To investigate the association between parental socioeconomic status (SES) and infant weight faltering in Japan.
• To determine if inequalities in weight faltering based on SES changed between 2001 and 2010.
• To inform social policies aimed at reducing disparities in infant growth.

Main Methods:

• Utilized two Japanese population-based birth cohorts (2001 and 2010).
• Assessed parental SES via household income and education at 6 months postpartum.
• Defined weight faltering as the slowest weight gain in 5% of infants; employed logistic regression and relative index of inequality.

Main Results:

• Infants in the lowest income quartile had a 1.29 (2001) and 1.27 (2010) times higher likelihood of weight faltering compared to the highest income quartile.
• The relative index of inequality for household income was 1.66 (2001) and 1.86 (2010), indicating significant income-related disparities.
• No substantial change in income-related inequalities in infant weight faltering was observed between the cohorts.

Conclusions:

• Lower household income in Japan is associated with an increased risk of infant weight faltering.
• Income-based disparities in infant weight faltering persisted without significant change from 2001 to 2010.
• The findings highlight the need for social policies to mitigate weight faltering inequalities linked to household income.