Gestión Documental o de documentos

Waist–hip ratio, reflecting central obesity, is higher in South Asians than Europeans.58,142,145,149,152,153

Logistic regression analysis of univariate association between glucose tolerance and various anthropometric variables showed a stronger association with waist–hip ratio than BMI. However, the waist–hip ratios were not different among any of the South Asian subgroups.137,152 _Conversely,

Yajnik et al. (2008)154 _{found that once adiposity had been taken into account, waist measurement}

did not contribute anything further. They studied insulin resistance and adiposity in groups of rural, poor urban and middle-class urban men in or near the city of Pune. The found that adiposity explained two-thirds of the differences in insulin resistance, which was commonest among the prosperous middle-class men. Half of the urban middle-class men were centrally obese. A third were overweight or obese if a BMI threshold of 25 kg/m2 _{was used. However, that}

threshold may be too high for South Asians. The mean BMI in the often adipose and centrally obese middle-class men was only 23.6 kg/m2_.

Cholesterol

South Asians, in particular females, have lower levels of total cholesterol58,136,145,155 _{and high-}

density lipoprotein cholesterol-C (HDL-C)58,153 _{than Europeans. Cappuccio et al. (1997)}136

reported 67% of South Asians having total cholesterol level of > 5.2 mmol/l compared with 78% of the Europeans. However, more recent studies have reported increasing levels of total cholesterol in South Asians and the difference narrowing, so that there was no significant difference in

cholesterol between South Asians and Europeans.144,152,156 _{Among the subgroups of Indians,}

McKeigue et al. (1991)58 _{reported high levels of total cholesterol in Sikhs (6.06 mmol/l) and the}

lowest levels in Gujarati Hindus (5.45 mmol/l; p < 0.001). However, the HDL-C is high among the Sikhs (1.22 mmol/l) and lowest in Muslim men (1.04 mmol/l; p < 0.001).

Diet

Cultural factors play a part in dietary habits. Grace et al. (2008)157 _{found that among the}

Bangladeshi population in Tower Hamlets, it was regarded wrong to serve healthier curries with reduced fat content to guests, because it might be seen as ‘inhospitable’. The same study noted that the community was well aware of diabetes and its risks.157

Effects of migration on risk factors

Studies have also compared the prevalence of diabetes and its risk factors in populations from the same community who have emigrated to westernised cultures, with those who still live in their own countries. Ramaiya et al. (1995)158 _{reported higher prevalence of IGT (in both sexes)}

newly diagnosed diabetes (in women) and hypercholesterolaemia (in men) in the Asian Indian Bhatia community from Gujarat living in Tanzania, and the same community, living in the UK. A more recent study by Patel et al. (2006)159 _{studied the cardiovascular risk factors among Gujaratis}

living in Britain and compared it with the non-migrant Gujaratis in India. Although there was no significant difference in prevalence of diabetes, the most striking factor between the migrants and indigenous population was on nutrition. There was increased dietary energy intake in the migrants with significant contribution by fat intake. Serum cholesterol, triglycerides, BMI, and waist–hip ratio were all higher in the Gujarati immigrants to the UK than those in India. This illustrates the risks imposed by migration and cultural adaptation among people from the same cultural, geographic and genetic background.

Physical activity

Physical inactivity is identified as an important risk factor for diabetes and CHD. Physical activity is much lower in South Asians than in Europeans.142,155,158,160 _{Fischbacher et al. (2004)}160

reviewed 12 studies of levels of physical activity and fitness in South Asians (Indians, Pakistanis and Bangladeshis). Results in adults consistently showed lower levels of physical activity in South Asians than in the general population or white groups (South Asians’ activity levels were ~ 50–75% of those of Europeans), regardless of the diverse sampling methods, mode of physical activity assessment and criteria for activity levels.

However, there were differences among the Asian groups. Fischbacher et al. (2004)160 _reported

that Bangladeshis had the lowest physical activity level. Similarly, the Health Survey for England7

reported that Indian, Pakistani and Bangladeshi men were 14%, 30% and 45% less likely than the general population to meet current guidelines for physical activity.

Greater differences were found in activity levels between South Asians groups and the general population in women than in men. Bangladeshi women had very low levels of physical activity compared with the general population, with only 21% achieving recommended levels of physical activity. A lower level of activity was also reported in older respondents in all ethnic groups. This difference was greater among Bangladeshi men and women and Indian women than among corresponding general population groups (13% and 18%, respectively, in Bangladeshi and Indian women aged 16–34 years compared with 1% and 2%, respectively, in the ≥ 55 years age group and 26% and 11%, respectively, in the general population). Fast and brisk walking, and participation in sports and exercise, were less commonly reported in South Asian women.

This reduced level of physical activity is in part due to cultural norms. Grace et al. (2008),157

30 Ethnicity

opposed to physical activity, such as walking) was seen as alien to the culture, and inappropriate behaviour, especially among women and older people. This was less so in later generations. The reasons included views about appropriate dress.

Comparing immigrants from the same community (the Bhatia community in Gujarat) in Tanzania and the UK, diabetes mellitus and cardiovascular risk factors except hypertension were high in people living in Tanzania compared with immigrants to the UK. The most striking difference was the levels of physical activity in the communities despite similar BMIs. Sedentary lifestyle was observed in 63–84% of Gujaratis in Tanzania compared with 26–29% in the UK. High levels of physical activity were observed in 8% of Gujaratis in Tanzania compared with 36% in the UK (p < 0.001).158

An older study by Samanta et al. (1991)155 _{from Leicester noted a marked difference in activity}

between South Asians and white people: 8% active compared with 33% active.

Carroll et al. (2002)161 _{noted that the barriers to physical activity in South Asian Muslim women}

were culture, language, religion, age and socioeconomic status. However, a pilot scheme of ‘exercise on prescription’ suggested that these barriers could be overcome.

Smoking and alcohol

Two studies have reported that smoking and alcohol consumption levels are lower in South Asians than in Europeans,58,146 _{although Bhopal et al. (2004)}162 _{noted that Bangladeshi men have}

high smoking rates (57%) compared with 32% in Pakistani and 14% in Indian men. A study by Chowdhury et al. (2006)156 _{reported a non-significant difference in smoking between South}

Asians and European (23.6% vs 22%; p = 0.46). Among Indians, smoking is more prevalent among Muslims and lower in Hindus and Sikhs because of their religious beliefs.58,136 Insulin resistance

Many of the features noted above are related to insulin resistance. In his 2007 Bloom Lecture, Felix Burden (2007)163 _{summarises the effects of the increased insulin resistance in South}

Asians as:

■ early development of IGT (but not so much IFG) ■ more rapid transition from IGT to diabetes ■ earlier onset of diabetes

■ higher prevalence of diabetes.

Knight et al. (1992)164 _{compared male manual workers of Asian origin (64% Muslims from}

Pakistan and the Punjab, 31% mainly Gujarati Hindus) and non-Asian origin in two textile factories in Bradford. Diabetes was observed in 13% of Asian and 4.5% of non-Asians.164 _Insulin

resistance was much commoner in the Asians. The serum insulin level at 2 hours after glucose load in Asians was double that in white people. Asians had more central obesity, but lower BMIs (24 kg/m2 _{vs 25 kg/m}2_).