The progression of the tobacco epidemic in India on the national and regional level, 1998-2016

Our analysis revealed that in India, the age-standardized prevalence of tobacco use at national level has been higher among men than women: i.e., it increased between 1998-1999 and 2005-2006 and declined from 2005-2006 to 2015–2016 among men, whereas it declined continuously among women. While for most of the states we observed a declining trend in tobacco use after 2005, men in the north-eastern states of Manipur, Mizoram, and Nagaland and women in the western state of Gujarat and the north-eastern state of Manipur showed an increasing trend in tobacco use. Similarly, we observed clear regional differences in tobacco smoking and smokeless tobacco over time, with more states showing an increasing prevalence in either tobacco smoking or smokeless tobacco. Prevalence of tobacco use has been higher than the national average for the north-eastern states as compared to other states/regions of India, and has been higher among men than women for all regions.

Our findings that the prevalence of tobacco use first increased and then declined over time, and that the prevalence of smoking was higher among men than women, are in line with the classical smoking epidemic theory [5]. According to the classical smoking epidemic model, the increase and later decline in smoking prevalence took more than 5–6 decades. occurring first among men and only 2–3 decades later among women, and with a maximum smoking prevalence of approximately 55% among men and approximately 32% among women. Such an extended smoking epidemic pattern with clear differences in timing between men and women has been observed for the majority of European and North American/Australasian countries [37], and in developing countries like China [6].

India, on the other hand, has a pattern that is quite distinct from the classical smoking epidemic model. The maximum levels of smoking prevalence for both men and women in India (17.5% for men; 1.2% for women) are considerably lower than those anticipated in the classical smoking epidemic model. In addition, the approximately similar timing of the increase and decrease in tobacco smoking among men and women differs from the patterns found in western countries. Moreover, the rather low prevalence levels in 1998/99 seem to suggest that India underwent an increase followed by a decline in the prevalence of tobacco use over a comparatively short period of time. In light of these apparent deviations from the classical smoking epidemic model, we suggest that India has experienced a ‘compressed tobacco epidemic’.

A potential explanation for the compression of the tobacco epidemic in India is that larger numbers of Indians did not take up smoking until the late 20th century, at a time when the hazards of tobacco consumption were well understood. By contrast, men in Europe and North America/Australasia first took up smoking in the first half of the 20th century, when the negative health consequences were largely unknown [5, 37]. Thus, tobacco use was increasing among Indians at a time when the negative effects of tobacco consumption on health were already very apparent [7], and prevention strategies had been established [38‐40]. The lack of social acceptance of tobacco use among women and increase in the price of smokeless tobacco [41] are among other factors that may have contributed to the prevalence of both, tobacco smoking and smokeless tobacco use being substantially lower among women in India than their counterparts in other countries [42, 43]. In addition, India stands out as one of the countries where prevalence of tobacco consumption has been substantially reduced since 2005 [44] through the introduction of a large number of tobacco control policies (Figure S2). For example, the country implemented the National Tobacco Control Programme (NTCP) in 2008 with the aim of reducing the burden of tobacco dependence [45]. More recently, India initiated an mCessation service, a mobile service designed to motivate people to quit smoking [46]. The implementation of these policies on a nationwide scale has helped to reduce tobacco consumption, which has, in turn, contributed to the compression of the tobacco epidemic.

We also expanded the classical smoking epidemic model by including the use of smokeless tobacco as an important, country-specific form of tobacco consumption. On a national level in India, smokeless tobacco consumption follows the trends for tobacco smoking, and therefore fits into the classical smoking epidemic framework. Although the maximum levels of smokeless tobacco use prevalence (19.28% for men and 5.06% for women) have been substantially lower in India than in other countries [46], they were higher than the prevalence of tobacco smoking for all of the time points, particularly for women. Thus, the use of smokeless tobacco cannot be ignored when studying the tobacco epidemic in India.

While for most of the states we observed a declining trend in tobacco use after 2005, men and women in few states showed an increasing trend in tobacco use. Although overall tobacco use increased only for 4 Indian states (Manipur, Mizoram, Nagaland and Gujarat); tobacco smoking and/or smokeless tobacco increased in two north, five north-eastern, 2 southern and one western Indian state. Increase in overall tobacco use in states can be attributed to increase in tobacco smoking among men in Manipur (10.85% increase) and increase in smokeless tobacco use among men in Mizoram (15.81% increase) and Nagaland (10.5% increase), and women in Gujarat (27.89% increase) and Manipur (22.71% increase) (Table S2). The continued rise in tobacco use in these states are most likely be related to social and environmental influence such as parental influence, lower educational status, attraction towards role models and cultural practices. That is, the continued rise in tobacco use in the north-eastern region is likely to a strong degree attributed to the high social acceptance of tobacco use and cultural practices [24, 31], less effective state policies [32] and greater availability of tobacco products [31, 32]. The continued increase in tobacco use among women in Gujarat is most likely due the fact that this state is the second largest producer of tobacco [47], and has a high employment of women in this sector [48].

A further explanation for the relatively high tobacco consumption levels currently observed in India is related to the tobacco regulations that were implemented in the 1990 and 2000 s, which were less effective in targeting bidi smoking and smokeless tobacco use [31, 32]. Indeed, additional analysis revealed that smoking prevalence is still relatively high in states with bidi smoking traditions (Table S1). In these states, women tend to smoke more bidis and use more smokeless tobacco, while smoking fewer cigarettes (Table S1). This pattern may be partially explained by the comparatively high levels of employment of women in the bidi industry [48], and by women’s preferences due their economic constraints to consume more bidis and smokeless tobacco than cigarettes [42]. Prevalence of tobacco use was observed to be highest among men and women in the north-eastern states as compared to other states in the country. In these states, prevalence of tobacco smoking and smokeless tobacco use was increasing continuously among men and was declining slowly among women, resulting in tobacco use prevalence that was much higher than the national average. These large regional difference may be a result of state specific higher cultural and societal acceptance of tobacco use [24, 31]; greater access and availability of tobacco products [31, 32]; less effective implementation of state policies, and lower levels of adherence to these policies [32]; and increased female employment in the tobacco sector [49]. Different geographical and particularly socio-economic differences between and within states may also be a driver for increased tobacco use in states [24, 31, 32]. Individuals with lower education status and belonging to less favourable economic strata are more likely to use tobacco [24]. Additionally, socioeconomic differences were seen to be more prominent for tobacco smoking than smokeless tobacco [24].

Despite the overall progress India made in reducing tobacco consumption, it remains a public health priority, not only because of the situation in the north-eastern regions, but also because in India as a whole, the levels of tobacco use in 2015–2016 were largely comparable to the levels in 1998–1999 (Table S2), and smokeless tobacco and bidi consumption still play a major role in many parts of the country (Table S1). The complex tax structure in India has kept taxes on cigarettes relatively low, and taxes on bidis and smokeless tobacco products very low, compared to other countries [41, 50]. Thus, bidis and smokeless tobacco products remain quite affordable. Whereas taxes on cigarettes account for approximately 38% of the retail price, taxes on bidis account only 9% of the retail price. These taxes are well below the tax rates on tobacco products recommended by the World Bank of 65–80% of the retail price [50, 51]. In 2011 in India, the price of a single cigarette was US$0.026, whereas the price of a single bidi was US$0.0033^51,52. Similarly, in 2016, retail price per pack of most brands of smokeless tobacco was US$0.10³⁷. A study by John et al. (2007) suggested that approximately 23 million people would stop smoking bidis and 4.7 million people would stop smoking cigarettes if taxes were increased from US$0.19 to US$1.33 per 1000 bidis (9–40% of the retail price) and from US$8.98 to US$50.27 per 1000 cigarettes (from 38 to 78% of the retail price) [51, 52].

Our study is the first to provide insights into the progression of the tobacco epidemic by gender across Indian states. For our study, we used several rounds of the NFHS to estimate the age-standardized smoking and smokeless tobacco prevalence. Specifically, we used information on tobacco consumption for men and women between 15 and 49 years of age, as the cumulative tobacco consumption levels between these ages are a strong predictor of adverse health consequences later in life [53, 54]. The NFHS has a huge sample size and uses the same sampling procedure across its different rounds to provide relatively accurate representation of the population at national and state levels [33], which is not the case in other sample surveys, like the Global Adult Tobacco Survey (GATS), the Global Youth Tobacco Survey (GYTS), and the National Household Survey of Drug and Alcohol Abuse in India (NHSDAA). For example, the GATS, which was used in the studies by Mishra et al. (2016) and Goel et al. (2014), has considerable under-sampling in the 10 states with highest levels of tobacco consumption [55]. In addition, discrepancies in reporting of the procedures used for data collection and quality assurance in GATS may have significantly affected its estimates of tobacco use prevalence [56]. Similarly, the NHSDAA covered only men from 25 states [57], and the GYTS was designed to collect information on tobacco use among young people between ages 13–15 only [58]. Moreover, the NHSDAA was conducted at only one point in time, while the GYTS was conducted at just two points in time. Using the NFHS for the present study was advantageous, as it is a repeated cross-sectional survey representing 99% of the Indian population. Prevalence of tobacco consumption was captured in the NFHS rounds using self-administered questionnaires, which meets the global standardized guidelines [59].

However, some limitations of our study should be taken into account when interpreting our results. First, we provide information only on current tobacco use, and not on the severity (duration/amount) of the consumption. This latter information is, unfortunately, not provided by the NFHS. Still, we believe that for studying the tobacco epidemic, the information provided by NFHS is reliable. Second, because the NFHS survey rounds were conducted with substantial time lags, the exact timing of the peak of the tobacco epidemic cannot be assessed using this data, especially among females. Third, the overall prevalence of tobacco use in the Indian population may be higher [44], as we focus only on 15–49 age group. Finally, the present study considered only the prevalence of tobacco use, while the classical smoking epidemic model also includes smoking-attributable mortality. This is certainly an important field for future research that will provide further insights into the overall health burden of tobacco smoking and smokeless tobacco in India. Another important perspective is to look into socio-economic differences within and across states and how they contribute to regional and national tobacco consumption patterns.