Association between dietary acid load and the risk of cardiovascular disease: nationwide surveys (KNHANES 2008-2011)

Abstract

Background: Acid-base imbalance has been reported to increase incidence of hypertension and diabetes. However, the association between diet-induced acid load and cardiovascular disease (CVD) risk in the general population has not been fully investigated.

Methods: This was a population-based, retrospectively registered cross-sectional study using nationally representative samples of 11,601 subjects from the Korea National Health and Nutrition Examination Survey 2008-2011. Individual CVD risk was evaluated using atherosclerotic cardiovascular disease (ASCVD) risk equations according to 2013 ACC/AHA guideline assessment in subjects aged 40-79 without prior CVD. Acid-base status was assessed with both the potential renal acid load (PRAL) and the dietary acid load (DAL) scores derived from nutrient intake.

Results: Individuals in the highest PRAL tertile had a significant increase in 10 year ASCVD risks (9.6 vs. 8.5 %, P < 0.01) and tended to belong to the high-risk (10 year risk >10 %) group compared to those in the lowest PRAL tertile (odds ratio [OR] 1.23, 95 % confidence interval [CI] 1.22-1.35). The association between higher PRAL score and high CVD risk was stronger in the middle-aged group. Furthermore, a multiple logistic regression analysis also demonstrated this association (OR 1.20 95 % CI 1.01-1.43). Subgroup analysis stratified obesity or exercise status; individuals in unhealthy condition with lower PRAL scores had comparable ASCVD risk to people in the higher PRAL group that were in favorable physical condition. In addition, elevated PRAL scores were associated with high ASCVD risk independent of obesity, exercise, and insulin resistance, but not sarcopenia. Similar trends were observed with DAL scores.

Conclusion: Diet-induced acid load was associated with increased risk of CVD, independent of obesity and insulin resistance.

Keywords: Atherosclerosis; Diet; Epidemiology; Risk factors.

Fig. 1

The flow diagram of subject inclusion and exclusion in the Korean National Health and Nutrition Examination Surveys (KNHANES IV and V)

Fig. 2

Differences in CVD risk according to PRAL tertiles. a Average ACC/AHA ASCVD 10 year risk scores. b Average ACC/AHA ASCVD 10 year risk scores in age groups. c Proportion of individuals with high ACC/AHA ASCVD 10 year risk (>10 %). d Proportion of individuals with high ACC/AHA ASCVD 10 year risk (>10 %) in age groups. Mean ± standard errors, *P < 0.05, **P < 0.001

Fig. 3

Differences in the CVD risk according to PRAL tertiles. a Average Framingham 10 year risk scores. b Average Framingham 10 year risk scores in age groups. c Proportion of individuals with high Framingham 10 year risk (>20 %). d Proportion of individuals with high Framingham 10 year risk (>20 %) in age groups. Mean ± standard errors, *P < 0.05, **P < 0.001

Fig. 4

Differences in the CVD risk according to DAL tertiles. a Average ACC/AHA ASCVD 10 year risk scores. b Average ACC/AHA ASCVD 10 year risk scores in age groups. c Proportion of individuals with high ACC/AHA ASCVD 10 year risk (>10 %). d Proportion of individuals with high ACC/AHA ASCVD 10 year risk (>10 %) in age groups. Mean ± standard errors, *P < 0.05, **P < 0.001

Fig. 5

The proportion of individuals with high ACC/AHA ASCVD 10 year risk (>10 %) stratified by age groups. a Diet-induced acid load defined by PRAL score. b Diet-induced acid load defined by DAL score. Dark and light boxes indicate the high-score group and the lowest score group, respectively. *P < 0.05, **P < 0.001

Fig. 6

Difference in CVD risk according to PRAL scores, stratified by metabolic status and physical activity. a Proportion of individuals with high ACC/AHA ASCVD 10 year risk stratified by overweight defined as BMI ≥23 kg/m², b regular exercise, c HOMA-IR with a cutoff point of 2.5, and d sarcopenia defined as ASM/BMI definition. The data are presented as OR with 95 % CI, NS non-significance; *P < 0.05, **P < 0.001

Fig. 7

Proportion of individuals with high ACC/AHA ASCVD 10 year risk according to sarcopenic status. a ASM/height² definition. b ASM/weight definition. The data are presented as OR with 95 % CI, NS non-significance; *P < 0.05, **P < 0.001