Analysis of energy intakes, physical activities and metabolic syndrome according to the income level in Korean elderly people: Korean National Health and Nutrition Examination Survey 2016‒2018

[Purpose] To determine the correlations of differences in the income level with the presence of metabolic syndrome (MetS), energy intake, and physical activity across Korean elderly populations. [Methods] We obtained data from 2,139 elderly individuals (aged >65 years) based on the Korea National Health and Nutrition Examination Survey (KNHANES) (2016‒2018). We analyzed the levels of physical activity (PA) and energy intake using the survey data. Moreover, we analyzed the differences in energy intake and PA levels according to the income level and MetS. [Results] Compared with the non-MetS group, the MetS group displayed significantly higher levels of waist circumference (p=0.000), triglycerides (p=0.000), systolic blood pressure (p=0.000), diastolic blood pressure (p=0.016), and fasting blood glucose (p=0.000) for both high and low income levels. However, the level of high-density lipoprotein cholesterol was significantly lower in the MetS group than that in the non-MetS group (p=0.000). The level of smoking in non-MetS men was significantly higher than that in MetS men across all participants (p=0.047). Except carbohydrate intake, the total energy intake (p=0.022), fat intake (p=0.009), and protein intake (p=0.005) were significantly lower in the MetS group than those in the non-MetS group for high income levels. We obtained similar results for low income levels. The two-way analysis of variance (ANOVA) did not identify an interaction between the income level and the presence of MetS; however, the total energy, i.e., the level of total energy intake, was significantly lower in participants with low income levels than in those with high income levels. For high income levels, transport PA (p=0.002), vigorous recreational PA (p=0.001), moderate recreational PA (p=0.001), and total PA (p=0.000) were significantly lower in the MetS group than those in the non-MetS group. For low income levels, moderate occupational PA (p=0.012), transport PA (p=0.018), and total PA ((p=0.000) were significantly lower in the MetS group than those in the non-MetS group. The total PA, i.e., the level of energy consumption, was significantly lower in the elderly with low income levels than in those with high income levels. [Conclusion] Regardless of the income level, the elderly with MetS exhibited low levels of energy intake and PA, compared with those without MetS. In addition, regardless of the presence of MetS, the elderly with low income levels exhibited lesser energy intake and PA. These findings implied the need for balanced nutrient intake and increased participation in PA as well as education and program development to prevent MetS in the elderly.