Our current study evaluated the CRF in Malaysian youths and compared them between the urban and rural youths in our country. To the best of our knowledge, the data that reported on this group of young adults is very scarce especially when comparing between the area of residence. Our study showed that CRF were significantly more prevalent among rural compared to urban youths, and the outcomes concurred with the Malaysian previous general population study14, 15. They reported that smoking, obesity, hypertension, diabetes and depression were identified as more prevalent among rural residents compared to urban14. Increasing urbanization and modernization may be one of the major causes to influence the more prevalent CRF in rural. The lifestyles changes in this population may have contributed to the current trend in our country and some other countries.
Prevalence of CRF between urban and rural populations are largely conflicting worldwide, and many factors may contribute to this for instance the countries’ Gross Domestic Product (GDP). Smoking, obesity, hypertension, diabetes and hyperlipidaemia, were more rampant in rural population of certain countries like Sweden and India16, 17, but reported to be on the contrary in other countries like China, Ghana and Peru18–20. Ezzati et al reported that CRF are expected to shift to low-income and middle-income countries and, with the persistent heavy burden of infectious diseases in these countries will further increase the global health inequalities21. Similarly, Rabin et al stated that GDP and obesity have a negative association in high-income European countries22. However, another study did not find any relationship between CRF (obesity, insufficient activity, systolic blood pressure, and fasting plasma glucose) with GDP. Comparably, Danaei et al indicated that a country’s GDP level does not indicate that there must be health behavior change and health improvement endeavors and suggested that the countries’ income has a rather indirect relationship with health behavior or health improvement endeavors23. However, majority of the aforementioned studies were conducted among general population without age grouping. The differences in socioeconomic, lifestyle and stress exposure across different age groups, the prevalence of CRF between general population and youths may be different.
Our study showed that rural group was significantly more overweight and obese, and has higher prevalence of family history with hypercholesterolaemia. This trend is interesting and also alarming at the same time showing that obesity is not entirely associated with the place of residence and urbanization or modernization may play an important role. In one study among 16 to 35 years old participants in a district in Malaysia, Pell et al reported that the prevalence was high with prevalence of overweight was 12.8% at ages 16–20 and 28.4% at ages 31–35 while obesity was 7.9% and 20.9% at the same age group respectively24. However, since it was only from one district, a comparison between rural and urban was not performed. They also highlighted that the pattern among this age group suggests that this is a significant period for change in health-related behaviours24. Other Malaysian studies looking at younger age group among the children and adolescents reported that the rural group had higher odds of overweight and obesity suggesting that rural environment may be more “obesogenic” in ways that a person-level analysis is unable to distinguish25. On contrary to another recent publication which reported that there was no significant difference in BMI status between rural and urban as well as between genders26. Interestingly, our neighboring country Indonesia reported that the prevalence of obesity was higher in urban children and adolescents compared to urban27. However, direct comparison is difficult due to the difference in the study group.
Despite the majority of CRF were more prevalent in rural youths in our study, urban youths had significantly higher LDL-c and TC compared to rural youths. Worse lipid profile is probably associated with high-fat diet or fast food which are more widely available in the city. Contrary to our findings, Nuotion et al reported that people living in urban areas had a more favourable CRF compared to rural residents. They reported that the general urban population had LDL-c, MS and Hba1c28, albeit without restricting the age of the subjects. These contradicting findings leave us the question of what is the factor that dictate the CRF among youths, if the location of residency is not the determining factor. A study in Indian young adult population (age 26–32 years) had attempted to associate Household Possession Score, individual education and paternal education status with CRF. The study consistently found that subjects with higher score of these socioeconomic status indicators were associated with more CRF29, regardless whether they are rural or urban residents, hypothesising that CRF is related to greater accessibility to food and less physically-straining job among higher socioeconomic status people.
If the main contributor of CRF among youths is socioeconomic status, the future preventive measure in preventing premature CVD death should focus in spreading awareness of healthy lifestyle among these high socioeconomic status youths, regardless if they are urban or rural residents. Higher education level can be an indicator of higher socioeconomic status, but since education coverage of Malaysian youths are quite uniform, additional information, such as household income, are required to deduce the cause of CRF among this group. However, some other studies in the Malaysian general population showed that better education is associated with less CRF for example obesity30. Our study found that other coronary risk factors like HDL, TG, diabetes mellitus, smoking, hypertension, central obesity and family history of CAD are not significantly different between urban and rural youths.
A significant strength of our study is the recruitment of a large number of participants from youth population. They were still not fully exposed to unhealthy lifestyle or therapeutic intervention, ie drug naïve, where they were not on anti-diabetic, anti-hypertensive, lipid-lowering agents and/or long-term antioxidant or anti-inflammatory therapy which may act as confounders. However, a perceived limitation is that the study is cross-sectional and hence is only able to demonstrate association rather than causal effect. The socioeconomic status of the subjects was also not being fully factored into the association with CRF in this study. Future longitudinal studies concentrating on this group of youths are vital to better understand the nature of the coronary risk profiles and aid in reducing the prevalence of CAD in later life.