Background:
Notwithstanding the importance of decreasing tobacco use to achieve Sustainable Development Goals' mortality reduction targets, evaluations of tobacco control programmes in low- and middle-income settings are scarce. We studied the impact of India's National Tobacco Control Programme (NTCP) on household-reported consumption of bidis and cigarettes using a Difference-in-differences (DID) analysis, typically used in econometrics for programme impact evaluation.

Methods:
Secondary analyses were conducted on three cross-sectional datasets from nationally representative Household Consumer Expenditure Surveys (CES) (1999-2000; 2004-05 and 2011-12). Their sample sizes varied between 100,000-125,000 households. The CES collected information on consumption and expenditure of 350 food and non-food items. Outcomes were: any bidi/cigarette consumption in the household during the past 30 days; and monthly consumption of bidi/cigarette sticks per person. DID two-part models were used to compare changes in outcomes over time and between districts with NTCP and without NTCP implemented, adjusting for socio-demographic characteristics and time-based heterogeneity.

Results:
There were no significant reductions in the proportion of households reporting bidi (adjusted odds ratio [AOR] 1∙04, 95% confidence interval [CI] 0∙84-1∙28) or cigarette consumption (AOR: 1∙01, 95% CI 0∙82-1∙26) in NTCP districts compared with non-NTCP districts. Among households that reported any bidi/cigarette consumption, we observed an overall reduction in the monthly per person consumption of bidi/cigarette sticks over time. However, these reductions were not significantly different between NTCP and non-NTCP districts (adjusted coefficients were: 0∙07 bidi sticks, 95% CI -0∙13-0∙28 bidi sticks; and -0∙002 cigarette sticks, 95% CI -0∙26-0∙26 cigarette sticks).

Conclusions:
Although the consumption of bidis and cigarettes had reduced in India between 1999-2000 and 2011-12, these reductions were not significantly different between NTCP and non-NTCP districts. Strengthening implementation and enforcement of tobacco control policies is vitally important to reduce the future burden of tobacco use in the country.