Based on a nationally representative dataset of South Korean population, over half Korean adults who aged 19–64 years have CMP, IP (23.1%) and COP(13.0%) were followed in order. CMP group tended to be older, male, laborers, less educated, had a lower income status and high-risk consumers of alcohol and smoking compared with the non-CMP group. We found that higher consumption of calcium, potassium, and fruits were negatively associated with CMP, while unhealthy dietary habits such as irregular meals and skipping breakfast were positively associated with CMP.
A previous representative study showed that Korean population has a high incidence of multimorbidity pattern including chronic disease such as cardiovascular disease (11, 33). Prevalence of multimorbidity was seen in 26.9% of Korean adults over the age of 40 years (33) and 86% of Korean adults over the age of 65 years (11). Our results are shown unique that multimorbidity patterns among Korean adults were CMP, IP, and COP, which is consistent with previous studies in other countries (3, 34), about 70% of adults have at least one multimorbidity pattern. Global population-based study presented that the most frequent patterns of multimorbidity across countries were cardiovascular and/or metabolic conditions (3, 34). In agreement with previous research studies (35, 36), we found CMP was the most largest pattern in Korean adults, which is linked to advanced age, lower education and income than non-CMP individuals.
Our analysis suggest that diet is a crucial factor in multimorbidity. Higher consumption of fruits was associated with lower prevalence of CMP. According to the Jiangsu Nutrition Study of Chinese adults, consumption of fruits, vegetables, and whole grain products were associated with healthier stages among multimorbidity such as coronary heart disease, stroke, hypertension and diabetes (16). Especially, 45.4% of mortality (a total of 702,308 cardiometabolic deaths in US adults) from heart disease, stroke, and type 2 diabetes was estimated positive association with dietary factors including low intakes of fruit, vegetable, nut/seed, seafood and high consumption of processed meat, sugar-sweetened beverages, and sodium (18). The possible biological reason could be explained by the phytochemicals and micronutrients present in fruits (16). These compounds increase the antioxidant capacity of serum and increase the formation of endothelial prostacyclin that prevents platelet aggregation and reduces vascular tone (37). Fruit and vegetable consumption is also associated with lower blood pressure and lower cholesterol and lipid level, which are main risk factors for cardiovascular disease (38). Thus, our results proves evidence-based beneficial effects on cardiometabolic health that suggests dietary factors are associated with the presence of CMP (38). Additionally, the CMP group consumed less sugar and sweetener (about 2 g on average), but higher beverage (about 30 g on average) than the non-CMP group. A previous study high levels of sugar-sweetened drinks or soft drink consumption is a risk factor of multimorbidity and increased the multiple chronic diseases (39). The mechanisms underlying the results between CMP and beverage consumption could relate to the rapid absorption and metabolic reaction of simple sugars in beverages (40).
With respect to nutrients, we found that calcium and potassium were associated with lower CMP. Calcium and potassium are effective in blood pressure regulation, prevent cardiovascular diseases and other health problems when combined with other essential nutrients (constituents of a varied diet) (41, 42). High intake of potassium might influence the prevalence of CMP, which is known to be involved in sodium excretion. Likewise, dietary sodium was not significantly associated with CMP in our results, which is inconsistent with previous studies where high dietary sodium was related to CMP mortality (43, 44). The reasons for the current result might be because the high sodium intake group ate more than twice the amount of vegetables than the low sodium group (data not shown), which could be due to the protective effects of vegetables on CMP.
We showed that health-related behaviors including meal frequency, smoking, and alcohol consumption are linked to CMP. Previous studies suggested daily breakfast consumption as well as the number of meals may help to prevent cardiometabolic disease due to decreasing the risk of adverse effects due to glucose and insulin metabolism (19, 45). Meanwhile, consumption of alcohol was a risk factor in men with prediabetes (OR = 1.49, 1.00-2.24). Low physical activity is also known to be a factor in the development of metabolic syndrome (13) which is not consistent with our results, smoking (14) and high-risk alcohol consumption (15) are well-known risk factors for the development of metabolic disorders. Particularly, current smokers (20 cigarettes per day≥) were observed higher times of prevalence of metabolic syndrome (OR = 2.24, 1.00-4.99) compared to never smokers (14). A cohort study reported that unhealthy lifestyle factors increased the likelihood of multimorbidity both men (5.23, 1.70–16.1); and women (1.95, 1.05–3.62) (15). Our results thus suggest that irregular meals and skipping breakfast are associated with higher CMP, as well as smoking and high-risk alcohol drinking, which are risk factors for CMP.
This study has several strengths. We used data from a recent nationally-representative dataset in South Korea and took into account its complex sampling design to provide representative estimates. It is the first study to estimate multimorbidity patterns in South Korean adults aged 19 to 64 years to characterize multimorbidity not only focusing in the elderly. Finally, our study considered various dietary factors as well as other lifestyle factors to facilitate multidimensional interpretation. Despite these strengths, this study has some limitations. First, our study is a cross-sectional design, and the results cannot suggest a cause-effect relationship. Second, this study could not include duration of chronic diseases due to a lack of data. Third, dietary intake assessed by 24-hour recall might not be representative of typical subject intake.