Hypothetical Interventions on Risk Factors for Cognitive Impairment among Chinese Older Adults: An Application of the Parametric G-Formula

Quantifying the effect of interpregnancy maternal weight and smoking status changes on childhood overweight and obesity in a UK population-based cohort

BACKGROUND

Maternal preconception and pregnancy exposures have been linked to offspring adiposity. We aimed to quantify the effect of changes in maternal weight and smoking status between pregnancies on childhood overweight/obesity (≥ 85th centile) and obesity (≥ 95th centile) rates in second children.

METHODS

Records for 5612 women were drawn from a population-based cohort of routinely collected antenatal healthcare records (2003-2014) linked to measured child body mass index (BMI) age 4-5 years. We applied the parametric G-formula to estimate the effect of hypothetical changes between pregnancy-1 and pregnancy-2 compared to the natural course scenario (without change) on child-2 BMI.

RESULTS

Observed overweight/obesity and obesity in child-2 at age 4-5 years were 22.2% and 8·5%, respectively. We estimated that if all mothers started pregnancy-2 with BMI 18·5-24·9 kg/m² and all smokers stopped smoking, then child-2 overweight/obesity and obesity natural course estimates of 22.3% (95% CI 21.2-23.5) and 8·3% (7·6-9·1), would be reduced to 18.5% (17.4-19.9) and 6.2% (5.5-7.0), respectively. For mothers who started pregnancy-1 with BMI 18·5-24·9 kg/m², if all smokers stopped smoking, child-2 overweight/obesity and obesity natural course estimates of 17.3% (16.0-18.6) and 5·9% (5·0-6·7) would be reduced to 16.0% (14.6-17.3) and 4·9% (4·1-5·7), respectively. For mothers who started pregnancy-1 with BMI ≥30 kg/m², if BMI was 18·5-24·9 kg/m² prior to pregnancy-2, child-2 overweight/obesity and obesity natural course estimates of 38.6% (34.7-42.3) and 17·7% (15·1-20·9) would be reduced to 31.3% (23.8-40.0) and 12.5 (8.3-17.4), respectively. If BMI was 25.0-29.9 kg/m² prior to pregnancy-2, these estimates would be 34.5% (29.4-40.4) and 14.6% (11.2-17.8), respectively.

CONCLUSION

Interventions supporting women to lose/maintain weight and quit smoking between pregnancies could help reduce rates of overweight/obesity and obesity in second children. The most effective interventions may vary by maternal BMI prior to the first pregnancy.

Air quality improvement and incident dementia: Effects of observed and hypothetical reductions in air pollutant using parametric g-computation

INTRODUCTION

No evidence exists about the impact of air pollution reduction on incidence of dementia. The aim of this study was to quantify how air quality improvement leads to dementia-incidence benefits.

METHODS

In the French Three-City cohort (12 years of follow-up), we used parametric g-computation to quantify the expected number of prevented dementia cases under different hypothetical interventions with particulate matter measuring <2.5 μm (PM_2.5 ) reductions.

RESULTS

Among 7051 participants, 789 participants developed dementia. The median PM_2.5 reduction between 1990 and 2000 was 12.2 (μg/m³ ). Such a reduction reduced the risk of all-cause dementia (hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.76 to 0.95). If all study participants were enjoying a hypothetical reduction of more than 13.10 μg/m³ (median reduction observed in the city of Montpellier), the rate difference was -0.37 (95% CI, -0.57 to -0.17) and the rate ratio was 0.67 (95% CI, 0.50 to 0.84).

DISCUSSION

These findings highlight the possible substantial benefits of reducing air pollution in the prevention of dementia.