Municipality-level estimates and trends in overweight and obesity in pregnant women in Sweden

Background

Overweight and obesity (OWOB) among pregnant women have increased, posing significant risks to maternal and child health. Although sociodemographic and regional inequalities in maternal OWOB are well documented, little is known about how these patterns have evolved over time at the municipality level in Sweden. This register-based study examined geographic variation and temporal changes in OWOB among pregnant women in Sweden and identified municipalities with the largest and smallest changes over time.

Methods

Data from the Swedish Medical Birth Register and sociodemographic data from national registers for 1997–99, 2006–08 and 2015–17 were accessed through Umeå SIMSAM Lab. The final analytical sample comprised 523357 women. Body mass index (BMI) was measured at the first antenatal care visit, and the outcome was overweight and/or obesity (OWOB; BMI≥25 kg/m²). Municipality-level differences in OWOB prevalence over time were visualized using maps and multilevel logistic regression analyses were performed.

Results

Approximately 90% of municipalities (263 of 288) experienced increases in OWOB, with the rest showing a decline. Municipality-level variation was small (ICC=1.2% in 1997–99, 1.7% in 2006–8 and 1.5% 2015–2017). Higher age, lower education, lower income and being born in Africa were consistently associated with OWOB across all time periods. Prevalence increased by more than 50 percentage points in 14 municipalities between 1997–99 and 2015–17. Eight of the municipalities that exhibited a decline in OWOB prevalence were in northern regions.

Conclusions

OWOB increased in most of the municipalities in Sweden over two decades. However, the magnitude of change varied across areas. Despite particularly large increases in some municipalities, overall municipality-level variation remained small. These findings enable decision-makers to visualize and compare municipality-level inequalities and support better targeted interventions for vulnerable population.

Key messages

• OWOB increased in most Swedish municipalities, but low ICC (1–2%) indicates limited geographic inequality and relatively uniform patterns across areas.

• Municipality-level analyses provide a precision public health tool to support efficient targeting of local-level interventions to high-burden areas.