Acculturation and evolving cardiovascular disease: An unhealthy dyad

Great winds are powerless to disturb the water of a deep well

Chinese proverb

Acculturation has been defined as the ‘adoption of or adaptation to a different culture’;¹ and for immigrants, this may result in the adoption of cardiovascular disease (CVD) risk factors. In terms of health indicators, immigrant populations vary considerably from every country and indeed even within an individual country. This editorial will be restricted to the Chinese immigrant population to various western countries. A Canadian study in 1999 showed that immigrant Chinese Canadians were less likely to die of CVD compared with immigrant South East Asian and Caucasian Canadians.² The 2016 European Guidelines on CVD prevention in clinical practice utilise different modifiers for their risk factor SCORE paradigm with South East Asians being at 1.4, whereas Eastern Asians have a modifier of 0.7.³ This may lead healthcare practitioners to conclude falsely that the Chinese immigrant population may be less susceptible to the maladaptive lifestyle habits of western countries.

In a previous issue of the European Journal of Preventive Cardiology, Jin et al.⁴ present the results of a prospective population-based cohort study of Chinese immigrants to Australia. This was a subset of the 45-and-Up Study, which is a large cohort study of New South Wales residents aged 45 years and older. The mean age of the Chinese immigrants was 59 years and the majority had been in Australia for at least 10 years. Three acculturation variables were used for analysis and included: (a) age at migration; (b) length of time since migration; and (c) other language(s) spoken at home. The cardiovascular endpoints were self-reported in the English language and included coronary heart disease (CHD) and stroke; however, some indicators, such as peripheral vascular disease, were not collected. The risk factors of hypertension, diabetes, dyslipidaemia, current smoking, overweight/obesity and physical inactivity were analysed. Important covariates of age, sex, educational attainment, marital status and proxies of socioeconomic status were analysed, but did not affect the results. None of the acculturation variables influenced the hard CVD endpoints. With greater exposure to acculturation, there was an increase in the incidence of diabetes and the presence of more than three risk factors. Because the study included only individuals with English language proficiency, the acculturation measures may not reflect the true prevalence of CVD risk factors in this population. Non-English-speaking immigrants may be less likely to be screened for CVD risk factors, due to lack of access and awareness. Furthermore, the results of the study may be an overestimation if non-English-speaking Chinese immigrants maintained their customary diet and perhaps had fewer CVD risk factors. A recent study by the same authors⁵ provides further details with respect to the risk factors for Chinese immigrants to Australia. These studies are both limited by their cross-sectional designs;^4,5 hopefully future studies can analyse these factors on a longitudinal basis.

So, what are some of the key findings? The findings are depicted in Figure 1, which represents a causal web illustrating the various factors influencing disease states and the interactions among them. Distal and proximal factors operate through both intermediate factors and directly on disease states. Some of the key CVD health determinants for immigrant Chinese to Australia and other countries are depicted here.

Distal factors

Jin et al.⁴ showed that those immigrating before the age of 18 years were more likely to develop obesity, diabetes and more than three risk factors. This may reflect an earlier adoption of western lifestyles.

Acculturation processes, and specifically acculturation stress, may have significant impacts on cardiovascular health and disease outcomes. Social integration that provides a sense of belonging and a network of social support can ameliorate the effects of cardiac risk factors.⁷ Cultural transition involves dealing with challenges such as discrimination and intergenerational and gender conflicts due to dissonant acculturation processes between family members. Pre and post-immigration circumstances, such as separation of families, may contribute to acculturation stress furthering social isolation.

Although the processes and mechanisms underlying acculturation’s effects on health are relatively unknown, age at the time of immigration and English language proficiency seem to invoke different acculturation processes. Chinese immigrants who immigrate after 20 years of age are 1.5–3 times more likely to experience major depression than those who immigrate before the age of 20 years.⁸ Immigrants who arrive as older adults may have less ability to speak English. The results are fewer opportunities to develop social relationships outside of the family unit or original ethnic group. English language proficiency is a major determinant of social integration and reflects the potential for immigrants to participate in the labour force. Asian men who speak English proficiently have lower rates of mental health disorders compared with non-proficient English speakers.⁹

The genetic determinants can include a predisposition to a higher percentage of body fat and increased abdominal obesity. This can predispose Asians to the metabolic syndrome and diabetes.¹⁰ There may be a greater susceptibility for atherosclerosis from traditional risk factors, as suggested by an increased intima-media thickness found in Chinese who have been ‘westernised’.¹¹

Proximal factors

The proximal factors include diet, physical activity, smoking and obesity. The sociocultural context, such as an individual’s attitudes or ability to assimilate toward host cultural orientation, may influence the degree of exposure and subsequent adoption of lifestyle behaviours. A maladaptive dietary regimen results from the adoption of highly processed foods, while leaving behind a traditional cuisine.¹² Traditional Asian diets provide ample carbohydrates and vegetables, but may contain high levels of sodium in condiments such as soy sauce. Hartwell et al.¹³ studied the extent of international (European and Asian) students’ food acculturation in the United Kingdom. A ‘push-pull’ model was developed to explain various food choices and adjustment was described as a dynamic and multifaceted process fluctuating as a result of individual, cultural and external factors.

Jin et al.⁴ found that physical activity showed a mixed picture, with men becoming less active with time, while women became more active. It was proposed that women may adapt to the cultural norms of activity of the host country more so than men.¹⁴ Lower activity levels have also been reported among Chinese Americans, with only 31% in Seattle engaged in physical activity.¹⁵

Although the rate of smoking showed no change with acculturation for Australian Chinese immigrants,⁴ tobacco use varies considerably within the Asian American subgroups. Prevalence estimates of current smoking depend on the settings or the regions where the studies were conducted, or whether only English-proficient subjects were included.

Physiological factors

Jin et al.⁴ found that Chinese immigrants living in Australia for more than 30 years, or who had immigrated as a child, were more likely to have at least three risk factors. A more detailed analysis of middle aged to older Chinese residents (compared to non-Chinese Australians) showed the estimated prevalence ratio (PR) to be lower for hypertension (PR 0.95), total cholesterol (PR 0.87) and obesity (PR 0.46).⁵

Acculturation and disease states

For various disease states, Jin et al.⁵ found that Chinese Australians had a lower prevalence of CHD (PR 0.67) and stroke (PR 0.67), but a higher prevalence of diabetes (PR 1.25). Despite a lower incidence of acute myocardial infarction (AMI) compared to whites, Chinese immigrants had a higher risk of mortality after AMI.¹⁶ A systematic review and meta-analysis of western-dwelling Chinese immigrants similarly found higher short-term mortality after the first diagnosis of cornary heart disease.¹⁷ The presence of atypical AMI symptoms, or lack of awareness of AMI symptoms, may result in a delay in seeking care for AMI and may explain more severe infarcts among Chinese patients compared with other patients. For Chinese immigrants with CVD, limited social integration and increased risk of mental health disorders may account for adverse CVD outcomes.

Perspectives and policy aspects/public health implications

The concept and measurement of acculturation is complex. The level of acculturation of Chinese patients affects their behaviour with respect to seeking medical care, as well as access and utilisation of cardiac care and other healthcare services. The more acculturated Chinese patients possess better language and cultural skills and tend to be more adept at navigating the complex terrain of a western healthcare system. Further studies could include ethnographic interviews to provide a better understanding of how cultural and environmental factors influence attitudes and behaviours related to cardiovascular health in the Chinese immigrant population.

The challenge on a political level was articulated in 2009 when President Barack Obama of the United States called for strategies to improve the health of Asian Americans and determine the health disparities in various subgroups. This led to a science advisory by the American Heart Association entitled Call to Action: Cardiovascular Disease in Asian Americans.¹⁸ For Chinese Americans (and other Asian subgroups), in addition to the traditional risk factors, it is important to determine the effects of emerging risk factors such as: lipoprotein (a); high-sensitivity C-reactive protein; and coronary artery calcification.¹⁸

Lack of awareness and knowledge about CVD and its risk factors are typical of many Asian immigrants. Thus, cardiovascular health promotion programmes are critical for this population. In some countries, Asian immigrants are less likely to have access to employer-based health benefits and are more likely to be uninsured or underinsured. Of those covered by health insurance, low levels of healthcare utilisation may result from language and cultural barriers affecting their ability to access healthcare. Health education materials are generally not designed for non-English speakers or people with low literacy. The lack of bilingual staff and limited culturally appropriate services in healthcare settings may discourage Asian immigrants from seeking needed healthcare. Western cultures value individualism, whereas Asians value family and group success over individual achievement.¹⁹ It follows that effective CVD prevention and education programmes involve family members and community representatives to explore appropriate channels of delivering health information and services. Community-designed health promotion strategies that incorporate health beliefs and cultural values of the immigrant community will ensure programme success. The ecological framework of health promotion that takes into account the broad interrelationships between the individual, the interpersonal and the socioenvironmental factors in determining health behaviour can be used as a model for health promotors and planners.²⁰

What should practitioners do?

Healthcare practitioners who treat patients of Chinese ethnicity need to ascertain the details of the immigrant experience (such as age when arrived and duration within the host country) and, in some cases, refugee experience (such as loss of family members or emotional trauma). In addition, the interplay between previously held health habits (diet, exercise) and those adopted from the host country need to be assessed. Evaluation of cardiovascular risk should use risk engines that have been validated for this population. Because Chinese immigrants appear to fare better than other immigrant populations, this should not lead to a false sense of security that CVD does not occur. Risk factors such as obesity should use Asian norms for appropriate waist circumference and body mass index (BMI). In particular, a BMI greater than 23 kg/m² should be used rather than a BMI greater than 25 kg/m² to define obesity.²¹ Finally, culturally sensitive interventions may prove to be efficacious for improving heart health. Some programmes for chronic disease management are able to provide intervention programmes in a local community centre with staff who are conversant in the language and customs of the immigrant population.²²

Conclusion

In conclusion, the health and wellbeing of a Chinese immigrant population is complex. Appropriate assessments of acculturation are multifaceted. Although the epidemiological risk for CHD may be lower than other populations, certain risk factors (such as hypertension and diabetes) are higher. The years of exposure to the influences of the host country can be detrimental. The Chinese proverb ‘Great winds are powerless to disturb the water of a deep well’ reflects ageless wisdom. In the context of this discussion, the ‘great winds’ can represent the powerful influences of acculturation and the ‘deep well’ can reflect the innate cultural identity and protective nature of the traditional lifestyle of an immigrant population.

Acknowledgements

The authors would like to acknowledge Nathan P Beahm at the EPICORE Centre, University of Alberta, for providing expert editorial support and guidance for this manuscript.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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