Effect of the national integrated demonstration area for the prevention and control of noncommunicable diseases programme on behavioural risk factors in China: a synthetic difference-in-differences studyResearch in context

Summary: Background: The government-led community-based Chinese National Integrated Demonstration Areas for the Prevention and Control of Noncommunicable Diseases programme was launched in 2011, but no rigorous impact evaluation has been conducted to date. We aimed to evaluate the causal effects of this programme on behavioural risk factors. Methods: We used data from the latest five waves of the China Chronic Disease and Risk Factor Surveillance. The primary outcome is a behavioural risk score combining current smoking, passive smoking, drinking in last month, regular exercise, body mass index, and waist circumference. We applied the synthetic difference-in-differences method and constructed synthetic controls from the non-demonstration areas with the outcome. The average treatment effects on the treated were estimated for overall effect and by short- (1–2), medium- (3–4), and long-term (6–7 years) effects. Findings: We identified 26 demonstration areas (N = 72,193) and 100 non-demonstration areas (N = 275,397). Participants in the demonstration areas had higher education and income levels and different pre-implementation trends than non-demonstration areas. Using synthetic controls instead of non-demonstration areas reduced these pre-implementation differences. Compared to the synthetic controls, declines were observed in current smoking (−1.78% [−4.51%, 0.96%]), passive smoking (−8.09% [−14.27%, −1.90%]), and drinking in last month (−4.04% [−8.75%, 0.67%]) but not in the other factors. Behavioural risk score declined by 1.05 short-term (95% CI: −1.84, −0.26), 1.15 medium-term (95% CI: −2.08, −0.22), 2.82 long-term (95% CI: −4.79, −0.85), and 1.54 overall (95% CI: −2.51, −0.56). Interpretation: The programme improved behavioural risk scores, primarily through reductions in the prevalence of smoking and drinking, and the effect was long-lasting. Our findings provided empirical evidence for utilizing an integrated prevention and control strategy to fight against NCD in China and other countries facing similar challenges. Funding: The China National Key Research and Development Program (2018YFC1315304 and 2017YFC1310902); National Natural Science Foundation of China (81872721).