The Indians residing in the country also share the same unfavourable characteristics as their migrant counterparts. Beginning in the 1960s through the 1990s, investigators in India have estiinated the prevalence. of CAD in several urban and lvral populations. The prevalence of CAD in urban lndia is Sour-fold higher than in the US. In a study from Delhi it has been found that CAD prevalence in the age group 25-64 years is more than three times higher in Delhi as compared to that in its 111ral backyard (9.7 per cent vs. 2.7 per cent). While them prevalence of CAD in urban Keralites is 14 per cent (17 per cent in Illen and 10 per cent in women) it decreases to 7 per cent in rural Thiruvanathapusam and reaches'as low as 3 per cent in rural North India. Siilgh et a1 had reported three ti~llcs higher prevalence of CAD in urban areas as compared to that in rural population (9 per cent vs. 3.3 per cent). In a rural population in Rajasthan, Gupta et a1 found a 3.5 per cent prevalence of CAD. Gujratis staying at Delhi were found to have lower prevalence of CAD than the native Delhi population. Even in women in Delhi the CAD prevaleilce is around 10 per cent. Studies performed in the last decade show a prevalence rate ranging between 7.6 per cent and 12.6 per cent for urban populations, and 3.1 per cent to 7.4 per cent for rural populations.
Rural-urban comparison shows that the prevalence in urban areas has increased from about 2 per cent in 1960 to 6.5 per cent in 1970, 7.0 per cent in 1980, 9.7 per cent in 1990 and 10.5 per cent in 2000 while in rural areas il increased horn 2 per cent in 1970 to 2.5 per cent in 1980,4 per cenl in 1990 and 4.5 per cent in 2000.This rural-urban difference in prevalence with two-fold increase in rural areas compared to about nine-fold increase in urban aseas during the last few decades has been accounted for by the differing prevalence of risk factors in these two groups.
Recently, Mohan and others have found a CAD prevalerlce of 11 per cent in an urban population in south India. This appears to be lower thil11 the prevalence of CAD obtained using similas criteria in immigrant Indian populatio~ls (1 4. per cenl in the T~inidad study, 4 per cent in the Southall study and 5.2 per cent in the SHARE study). However, in terms of absolute numbers, there is a very steep growth in CAD cases in both urban and rural areas or India. In urban populalions the numbers have increased from 4.5 million in 1970 to 5.6 million in 1980 and 14.1 million in the year 2000. In rural populalions the numbers have grown from 4.1 million in 1970 to 6.4 ~llillion in 1980 and 15.7 million in the year 2000. The epidemiological studies show that there are at present about 30 nlillion CAD patients in the country. However as epiden~iological studies exclude many patients vrith silent and asympton~atic CAD, the actual numbers may be much higher than the estimated figure. The CAD sale in India is expected to rise in parallel with the increase in life expectancy. The average life expectancy has increased from 4 1 years in 1951 to 61 years in 1991 and is anticipated to reach 72 years in 2030; this could lead to a huge rise in CAD prevalence in coming years.
Like their immigrant counterparts, CAD occurs early in Indians and the age of presentation of acute corollary syndrome is about 5 to 10 years earlier in Indian patients. An Indian multicentre study reported that acute coronary syndron~es occui~ed at a mean age of 56.6 + 12 years in men and 61.8 + 10 y e a s in women,compared to average age of 66.0 + 0.05 years in developed countries. As far as the mortality is concerned, the situatioil is alarming in India. GBD study reported that of a total of 9.4 nlillion deaths in India in 1990, one quarter (2.3 miIlion) of dea6s were due to Cardio-vascular diseases - of which 1.2 million were due to CAD and 0.5 million due to stroke. It has been predicted that by 2020, there would be a 11 1 per cent increase in Cardio-vascular deaths in India, compared to 77 per cent for China, 106 per cent for other Asian countries and only 15 per cent for econon~ically developed countries.
Rural-urban comparison shows that the prevalence in urban areas has increased from about 2 per cent in 1960 to 6.5 per cent in 1970, 7.0 per cent in 1980, 9.7 per cent in 1990 and 10.5 per cent in 2000 while in rural areas il increased horn 2 per cent in 1970 to 2.5 per cent in 1980,4 per cenl in 1990 and 4.5 per cent in 2000.This rural-urban difference in prevalence with two-fold increase in rural areas compared to about nine-fold increase in urban aseas during the last few decades has been accounted for by the differing prevalence of risk factors in these two groups.
Recently, Mohan and others have found a CAD prevalerlce of 11 per cent in an urban population in south India. This appears to be lower thil11 the prevalence of CAD obtained using similas criteria in immigrant Indian populatio~ls (1 4. per cenl in the T~inidad study, 4 per cent in the Southall study and 5.2 per cent in the SHARE study). However, in terms of absolute numbers, there is a very steep growth in CAD cases in both urban and rural areas or India. In urban populalions the numbers have increased from 4.5 million in 1970 to 5.6 million in 1980 and 14.1 million in the year 2000. In rural populalions the numbers have grown from 4.1 million in 1970 to 6.4 ~llillion in 1980 and 15.7 million in the year 2000. The epidemiological studies show that there are at present about 30 nlillion CAD patients in the country. However as epiden~iological studies exclude many patients vrith silent and asympton~atic CAD, the actual numbers may be much higher than the estimated figure. The CAD sale in India is expected to rise in parallel with the increase in life expectancy. The average life expectancy has increased from 4 1 years in 1951 to 61 years in 1991 and is anticipated to reach 72 years in 2030; this could lead to a huge rise in CAD prevalence in coming years.
Like their immigrant counterparts, CAD occurs early in Indians and the age of presentation of acute corollary syndrome is about 5 to 10 years earlier in Indian patients. An Indian multicentre study reported that acute coronary syndron~es occui~ed at a mean age of 56.6 + 12 years in men and 61.8 + 10 y e a s in women,compared to average age of 66.0 + 0.05 years in developed countries. As far as the mortality is concerned, the situatioil is alarming in India. GBD study reported that of a total of 9.4 nlillion deaths in India in 1990, one quarter (2.3 miIlion) of dea6s were due to Cardio-vascular diseases - of which 1.2 million were due to CAD and 0.5 million due to stroke. It has been predicted that by 2020, there would be a 11 1 per cent increase in Cardio-vascular deaths in India, compared to 77 per cent for China, 106 per cent for other Asian countries and only 15 per cent for econon~ically developed countries.
Rural-Urban Difference
One of the imporlant characteiislics of CAD in Indians has been a clear gradient of increasing prevalence of CAD and the risk factors observed in many studies from the rural to the semi-urban to the urban popnlation, confirming an epideiniological trend. A study in Northern India has observed that compared to the villages, the age and sex-adjusted prevalence odds ratio of CHD was 1.9(95 per cent CI; 1.1-3.2) in the towns and 4.9 (95 per cent CI; 2.9-8.2) in the city.Most of the risk factors for CAD, i.e., high blood pressure, diabetes, obesity,physical inactivity, the quantity of food consumed, and lipid and insulin levels,were significantly higher in the urban population. Smoking, however, was less common in the ui'ban areas, while drinking was equally prevalent among the urban and rural communities. A recent review of Indian studies has also concluded that the rates of CHD, Hypei-tension, diabetes and obesity are very low among the rural population of India, and high in many 01 the metropolitan cities.Socio-cultural factors which can be considered to constilute an 'urban way oC life'are probably playing a significant role in the causation of CHD. According to Marmot and Syme, acculturaLion plays an important role in CHD causation. In England, the rates of CHD were Sound to be higher among Lhc rnore 'westernized'Indians than those with a more 'lraditionnl' approach, even after controlling for the effects of Lhe conventional risk factors for CHD.
The lirestyle in the villages is still very traditional. For one, a vegetarian diet is the norm and not much fried food is consumed. Further, agricultural work demands strenuous physical activity, leaving little rooin for obesity. Despite the fact that smoking is very common in the villages, the prcvalence of CHD is lower than in the urban population. The major risk factor for CHD in the urban population is the lack of physical work and consuml~tion of more fcood, both of which havc resulled in a much higher level of obesity in the urban than in the rural areas. The levels of Icholesterol and insulin were also significantly higher in urban areas. Obesity leads to insulin resistance, and makes a person more prone to diabetes, glucose intolerance and Hypertension. Insulin resistance has been demonstrated among overweight individuals even in rural areas. There is also marked dilference in the level of fasting and post-glucose load insulin between the rural and urban areas.
The risk factors for Hypertension, such as obesity, as well as ils prevalence, have nearly doubled among the urban population of Chandigarh in the last 30 years.It seems that dietary and activity patterns are more involved than is smoking in the etiology of the higher prevalence of CHD anlong the urban population of northern India. It appears that the urban lifestyle is conducive to the ~nanifeslation of the metabolic syndro~ne in Indians, as reported by McKeigue anlong South Asians living in London. Therefore, it has been suggested that retaining the traditional way of life as primordial preve~ltion is advisable in order to prevent the emergence of a CAD epidemic in the developing count~ies.
In summary, the available data suggest that
i) the prevalence of CAD among native Indians is high but less than that among immigrant Indians;
ii) there is a definite urban-rural diffesence in disease prevalence with pi-cvalence higher in url>an population;
iii) there is likelihood of a north-south divide with prevalence higher in the South than in the North of the conntry; iund
iv) the propensity for premature, severe and extensive lesions wilh high mortality is also applicable for the resident Indians.
One of the imporlant characteiislics of CAD in Indians has been a clear gradient of increasing prevalence of CAD and the risk factors observed in many studies from the rural to the semi-urban to the urban popnlation, confirming an epideiniological trend. A study in Northern India has observed that compared to the villages, the age and sex-adjusted prevalence odds ratio of CHD was 1.9(95 per cent CI; 1.1-3.2) in the towns and 4.9 (95 per cent CI; 2.9-8.2) in the city.Most of the risk factors for CAD, i.e., high blood pressure, diabetes, obesity,physical inactivity, the quantity of food consumed, and lipid and insulin levels,were significantly higher in the urban population. Smoking, however, was less common in the ui'ban areas, while drinking was equally prevalent among the urban and rural communities. A recent review of Indian studies has also concluded that the rates of CHD, Hypei-tension, diabetes and obesity are very low among the rural population of India, and high in many 01 the metropolitan cities.Socio-cultural factors which can be considered to constilute an 'urban way oC life'are probably playing a significant role in the causation of CHD. According to Marmot and Syme, acculturaLion plays an important role in CHD causation. In England, the rates of CHD were Sound to be higher among Lhc rnore 'westernized'Indians than those with a more 'lraditionnl' approach, even after controlling for the effects of Lhe conventional risk factors for CHD.
The lirestyle in the villages is still very traditional. For one, a vegetarian diet is the norm and not much fried food is consumed. Further, agricultural work demands strenuous physical activity, leaving little rooin for obesity. Despite the fact that smoking is very common in the villages, the prcvalence of CHD is lower than in the urban population. The major risk factor for CHD in the urban population is the lack of physical work and consuml~tion of more fcood, both of which havc resulled in a much higher level of obesity in the urban than in the rural areas. The levels of Icholesterol and insulin were also significantly higher in urban areas. Obesity leads to insulin resistance, and makes a person more prone to diabetes, glucose intolerance and Hypertension. Insulin resistance has been demonstrated among overweight individuals even in rural areas. There is also marked dilference in the level of fasting and post-glucose load insulin between the rural and urban areas.
The risk factors for Hypertension, such as obesity, as well as ils prevalence, have nearly doubled among the urban population of Chandigarh in the last 30 years.It seems that dietary and activity patterns are more involved than is smoking in the etiology of the higher prevalence of CHD anlong the urban population of northern India. It appears that the urban lifestyle is conducive to the ~nanifeslation of the metabolic syndro~ne in Indians, as reported by McKeigue anlong South Asians living in London. Therefore, it has been suggested that retaining the traditional way of life as primordial preve~ltion is advisable in order to prevent the emergence of a CAD epidemic in the developing count~ies.
In summary, the available data suggest that
i) the prevalence of CAD among native Indians is high but less than that among immigrant Indians;
ii) there is a definite urban-rural diffesence in disease prevalence with pi-cvalence higher in url>an population;
iii) there is likelihood of a north-south divide with prevalence higher in the South than in the North of the conntry; iund
iv) the propensity for premature, severe and extensive lesions wilh high mortality is also applicable for the resident Indians.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.