has fallen by 67% (Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004). In this study, tobacco consumption showed no signiﬁ- cant differences in various social classes in men, although among women it was signiﬁcantly more common among social classes 4 and 5 compared with higher social classes. Increased chewing of raw tobacco is common among lower social classes in India, whereas social class 1–3 prefer to chew ﬂavored tobacco (Gupta et al 1980; Singh et al 1997a, 1997b, 1999). Causes of death by social class and tobacco consumption are given in Table 3. Circulatory diseases were the common cause of death in both sexes, ie, 29.3% in men and 28.6% in women, in our study. Malignant diseases were also major causes of death in men (5.5%) and in women (6.4%). Circulatory diseases and diabetes as cause of death were observed in 31.3% (n = 695) of the decedents. Chronic bronchitis and asthma as the causes of death were observed among 7.0% of men and 7.7% of women. Other causes of death such as infections (41.1%, n = 915), injury (14.0%, n = 313), pregnancy and prenatal (0.72%, n = 15), miscel- laneous (9.12%, n = 202) were observed among social classes 4 and 5, in both sexes (Table 3). Social classes 1–3 were signiﬁcantly associated with deaths due to circulatory diseases compared with social class 4 and 5, in both sexes. However, deaths due to cancers were signiﬁcantly more common among social class 1 women (breast cancer) without such an association in men (Table 3). Our study shows that social class has become an important determinant of mortality in the urban population of north India (Singh et al 2005). In the light of WHO estimates, it seems possible that there appears to be a decline in deaths due to infection, and increased death rate due to CVD and diabetes in higher social classes. Whereas in lower social classes infections remain the major cause of death (Gupta et al 1980; Singh et al 1997a, 1997b; Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004). This phenomenon may be due to aging of the population and economic development causing rapid changes in diet and lifestyle resulting in a nutritional transition from under-nutrition to over-nutrition (Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004; INTERHEART 2006). We also found that tobacco intake showed no social class differences among men. However, it was signiﬁcantly associated with deaths due to circulatory diseases and cancers. It seems that the stage at which hypertension, diabetes, and coronary artery disease (CAD) and cancer emerge as signiﬁcant causes of death, corresponds to a life expectancy level between 50–60 years and at this level cardiovascular mortality accounts for 15%–25% of all deaths (Yusuf et al 2001a, 2001b; WHO International Journal of COPD 2007:2(2) Tobacco deaths in India 2002; Sachs 2004). In developed countries (Foley et al 2002; Puska et al 2003; Schiafﬁno et al 2003; Schoenborn et al 2003), eg, in the United States during the same period (2001) among male and female subjects aged 25–64 years with an education level of 12 years, mortality ratios of 3.09 and 20.90, respectively, were reported as compared with those having higher educational levels. This ﬁnding is universal in the developed countries, but not in the developing countries because the developing economies have not yet learned the methods of prevention of diseases (Singh et al 1997a, 1997b; Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004). In south India, life expectancy has become as great as in developed countries, and there is a marked decrease in under-nutrition and deaths due to infections, but morbidity and mortality due to circulatory diseases are increasing (Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004; INTERHEART 2006). Level of education has become a very good indicator of social class in the Western world (Yusuf et al 2001a, 2001b; WHO 2002; Sachs 2004; INTERHEART 2006). There are several fac- tors, which may explain the impact of social class on health in developed countries: smoking behavior, obesity, physical activity, nutrition, and psychosocial factors, with all favor- ing the higher social classes. In developing countries such as India, China, Sri Lanka, and Brazil, enormous occupational physical activity in lower social classes is protective against morbidity and mortality due to circulatory diseases while they continue to have more deaths due to infections and poor nutritional status. Unfortunately, the impact of better education due to lack of health education, possibly, has not yet started in these countries, as well as among Indian im- migrants to developed countries (Balarajan 1991; Hahn 1992; Jha et al 1993). This delay has resulted in a marked increase in mortality and morbidity due to circulatory diseases and neoplasms with increase in social class in conjunction with improvement in nutritional status as observed in our study (Tables 3–5; INTERHEART 2006). Tobacco consumption was highest among young decedents (Table 2), which may be the cause of increased susceptibility in Indians to die from vascular diseases (Balarajan 1991; Hahn 1992; Jha et al 1993). In India, life expectancy increased from 41.2 years in the decade 1951–1961, to 61.4 years for the 1991–1996 period, causing a great increase in the population at risk from mortality and morbidity due to noncommunicable diseases (Singh et al 1997a, 1997b, 1999; Yusuf et al 2001a, 2001b; WHO 2002; Kesteloot 2003; Sachs 2004; INTERHEART 2006). There has been a marked increase in tobacco production and consump- tion in the last four decades in India, according to various 183