Factors Influencing Hypertension in Korean Adults: Results from the Korea National Health and Nutrition Examination Survey of the Korea Disease Control and Prevention Agency

Abstract

Hypertension among adults in Korea is steadily increasing, yet limited research has explored the contributing risk factors in this population. This study aimed to identify the factors associated with hypertension in Korean adults, with a particular focus on informing prevention strategies. This study utilizes the data from the Korea National Health and Nutrition Examination Survey, conducted by the Korea Disease Control and Prevention Agency, specifically examining blood heavy metal levels and dietary habits. The analysis included 8,025 adults aged 30 years and older. Significant associations were observed between hypertension and dietary intake of fish, shellfish, and meat, whereas no significant associations were found with grain and vegetable consumption. Regarding serological indicators, all variables-including blood glucose, HDL triglycerides, and total cholesterol-showed significant associations with hypertension. Among the heavy metal indicators, only blood cadmium levels were statistically significantly associated with hypertension; mercury and lead showed no significant effects. These findings suggest that hypertension in Korean adults is influenced by both dietary and environmental factors. Given the role of hypertension in increasing the risk of cardiovascular and cerebrovascular diseases and in reducing life expectancy, this study underscores the importance of improving dietary habits and promoting regular physical activity as key strategies for hypertension prevention.

1. Introduction

According to the 2023 statistics released by statistics korea, the leading causes of death in korea were cancer, cerebrovascular disease, and heart disease, with cerebrovascular disease accounting for a substantial proportion of mortality [1]. hypertension is a major modifiable risk factor for cerebrovascular disease and other cardiovascular outcomes [2]. hypertension is commonly classified as essential (primary) or secondary hypertension [3]. although the pathogenesis of primary hypertension remains unclear, it is closely associated with lifestyle and metabolic factors such as aging, excessive salt intake, psychosocial stress, obesity, physical inactivity, alcohol consumption, and smoking [4]. secondary hypertension, which accounts for approximately 10% of all hypertension cases, may result from adrenal or renal disorders, medication use, and obstructive sleep apnea [5].

Previous studies have identified several risk factors for hypertension, including age, resting pulse rate, baseline blood pressure, obesity, diabetes, dyslipidemia, family history, elevated serum cholesterol, and stress [6–8]. in addition to these conventional risk factors, environmental exposures have increasingly been recognized as potential contributors to elevated blood pressure. heavy metals such as lead, mercury, and cadmium are known to induce oxidative stress, endothelial dysfunction, and renal impairment, which may contribute to the development of hypertension [9,10]. because hypertension is often asymptomatic until serious complications occur, it is frequently described as a “silent killer,” highlighting the importance of early identification and prevention [11,12].

Therefore, this study aimed to investigate factors associated with hypertension among korean adults using data from the korea national health and nutrition examination survey (knhanes) conducted by the korea disease control and prevention agency (kdca). this study is a revised and expanded analysis based on kim hyun-mi’s doctoral dissertation and applies updated statistical methods using knhanes data [24]. specifically, we examined the associations of dietary habits, serological indicators, and blood heavy metal concentrations (lead, mercury, and cadmium) with hypertension [13–15].

The study addressed the following research questions:

(1) what is the distribution of hypertension among korean adults?

(2) are dietary habits associated with hypertension?

(3) are serological indicators associated with hypertension?

(4) are blood heavy metal concentrations associated with hypertension?

2. Methods

2.1 Study design and participants

This study employed a cross-sectional design using data from knhanes conducted by the kdca. knhanes includes blood heavy metal measurements (cadmium, lead, and mercury) in a subsample of participants and has been conducted annually since 2005, except for 2007 [13]. for this analysis, data from survey years 2010 to 2017 were used, excluding 2014 and 2015 due to data availability for key variables.

Among 15,600 respondents in the relevant survey periods, 8,025 adults aged 30 years or older with complete information on blood pressure, dietary habits, blood heavy metal concentrations, and covariates were included in the final analysis.

2.2 Statistical analysis

All statistical analyses were performed using ibm spss statistics. because knhanes employs a complex, multistage, stratified sampling design, sampling weights, stratification variables, and primary sampling units were applied to obtain nationally representative estimates [13]. continuous variables are presented as weighted means with standard errors, and categorical variables are presented as weighted percentages.

Differences between participants with and without hypertension were examined using complex-samples t-tests for continuous variables and complex-samples chi-square tests for categorical variables. complex-samples logistic regression analyses were conducted to estimate odds ratios (or) and 95% confidence intervals (ci) for factors associated with hypertension. separate models were constructed for blood mercury, blood lead, and blood cadmium, adjusting for demographic characteristics, health behaviors, weight status, serological indicators, and dietary variables [16–18]. statistical significance was set at p ≤ 0.05.

3. Results

3.1 General distribution of hypertension

The general characteristics of participants according to hypertension status are presented in Table 1. hypertension prevalence was highest among individuals aged 60–69 years, whereas the largest proportion of non-hypertensive participants was observed in the 40–49-year group (p<0.001), consistent with previous epidemiological findings [6,7]. participants with hypertension were more likely to have an education level of middle school or lower, while those without hypertension were more likely to have completed high school or higher (p<0.001).

Table 1. General statistical distribution of patients with hypertension.

Alcohol consumption differed significantly between the two groups (p=0.026), which aligns with earlier studies reporting associations between drinking behavior and blood pressure [4,17]. physical activity was reported by 80.8% of participants with hypertension and 76.2% of those without hypertension (p<0.001). weight status also differed significantly (p<0.001); normal weight and obesity were similarly prevalent in the hypertension group, whereas normal weight predominated in the non-hypertension group. no significant differences were observed for sex or smoking status.

3.2 Dietary habits and hypertension

Table 2 shows the distribution of dietary habit scores according to hypertension status. fish intake scores were significantly higher among participants with hypertension than among those without hypertension (t=5.47, p<0.001), and shellfish intake scores were also higher in the hypertension group (t=6.26, p<0.001). meat intake scores were significantly higher among participants with hypertension (t=2.06, p=0.039). grain and vegetable intake scores were not significantly associated with hypertension (p>0.05). these findings partially align with previous research suggesting that dietary patterns involving animal-based foods may influence blood pressure [13,16].

Table 2. Distribution of hypertension according to dietary habits.

3.3 Serological indicators and hypertension

As shown in Table 3, all examined serological indicators, including blood glucose, hdl cholesterol, triglycerides, and total cholesterol, were significantly associated with hypertension (all p<0.05). these results are consistent with prior studies demonstrating close relationships between metabolic abnormalities and hypertension [6,8].

Table 3. Distribution of hypertension according to serological indicators.

3.4 Heavy metals and hypertension

Multivariable logistic regression analyses are presented in Tables 4–6. blood mercury concentration was not significantly associated with hypertension after adjustment for covariates, consistent with previous findings reporting inconsistent associations between mercury exposure and blood pressure [15]. similarly, blood lead concentration showed no significant association with hypertension, although earlier studies have reported mixed results [9,14]. in contrast, blood cadmium concentration was significantly associated with hypertension in the fully adjusted model (or=1.162, 95% ci=1.062–1.272), supporting prior evidence linking cadmium exposure to vascular and renal dysfunction [10,14].

Table 4. Factors affecting hypertension according to blood mercury concentration.

*P<0.05, ** P<0.01

Table 5. Factors affecting hypertension according to blood lead concentration.

*P<0.05, ** P<0.01

Table 6. Factors affecting hypertension according to blood cadmium concentration.

*P<0.05, ** P<0.01

4. Discussion

This study investigated factors associated with hypertension among korean adults using nationally representative knhanes data. the findings indicate that hypertension is associated with dietary habits, metabolic indicators, and environmental exposure to cadmium, while mercury and lead showed no significant associations.

Hypertension prevalence was higher among older adults and those with lower educational attainment, consistent with previous population-based studies [6,7]. dietary analysis showed that higher intake of fish, shellfish, and meat was associated with hypertension, whereas grain and vegetable intake was not. differences between the present findings and earlier studies may be attributable to variations in dietary assessment methods and survey periods [13].

All serological indicators examined were significantly associated with hypertension, supporting existing evidence that hypertension frequently coexists with metabolic dysregulation [6,8]. among the heavy metals examined, only cadmium showed a significant association with hypertension. cadmium exposure has been linked to oxidative stress, renal dysfunction, and endothelial damage, which may contribute to elevated blood pressure [10,14]. the absence of significant associations for mercury and lead may reflect differences in exposure levels or population characteristics [9,15].

This study has several limitations. its cross-sectional design precludes causal inference, and dietary intake was assessed using self-reported measures. nevertheless, the use of a large, nationally representative dataset strengthens the generalizability of the findings.

5. Conclusion

This study identified key factors associated with hypertension among korean adults using knhanes data. dietary habits, adverse metabolic profiles, and blood cadmium concentration were significantly associated with hypertension, whereas blood mercury and lead were not. these findings underscore the importance of comprehensive prevention strategies, including lifestyle modification, metabolic risk management, and environmental exposure reduction. promoting healthy dietary habits, regular physical activity, smoking cessation, and moderate alcohol consumption may contribute to lowering blood pressure and preventing hypertension [16–23]. the results provide valuable evidence to inform public health strategies aimed at reducing the burden of hypertension in korea.