The total number of subjects was 5,169 and 36.2% were men. The mean age of subjects was 53.9 ([SD] 11.2) years, 53.6 (11.4) years for men, 54.1 (11.0) years for women. The prevalence of CKD was 17.7% (15.7% in men, 18.9% in women). The numbers of subjects with eGFR of 90 mL/min/1.73m2 or higher, 60-89 mL/min/1.73m2, 30-59 mL/min/1.73m2, or ≤30 mL/min/1.73m2 were 1,194 (23.1%), 3,058 (59.2%), 913 (17.7%), and 4 (0.08%) respectively. The number of subjects with positive proteinuria was 67 (1.3%). Because the percentage of those subjects was very small, we did not use the findings of proteinuria for the definition of CKD. The number of subjects with hyperlipidemia was 1,891 (36.6%), of which 85 (1.7%) had been treated. The number of the subjects with the TG ≥150 mg/dL alone, TC ≥220 mg/dL alone, or both TC ≥220 mg/dL and TG ≥150 mg/dL were 860 (16.7%), 610 (11.8%), and 410 (0.79%), respectively. The prevalence of CKD in each age group of 30-39, 40-49, 50-59, and ≥60 years were 0.8, 7.6, 11.5, and 27.3% in men and 0.4, 5.8, 23.1, and 27.9% in women, respectively (Figure 1).
Table 1 shows the general characteristics of CKD and non-CKD subjects. Age, the percentage of men, BMI, SBP, DBP, TC, TG, hyperlipidemia, and BS were higher in the CKD group than in the non-CKD group. No significant differences were observed in the prevalence of diabetes between the two groups. The percentage of subjects with current smoking and alcohol habits was lower in the CKD group than in the non-CKD group.
Table 2 shows that age (p<0.001), sex (p<0.05), SBP (p<0.001), and hyperlipidemia (p<0.001) were associated with reductions in eGFR in a multiple linear regression analysis model.
Table 3 shows the OR for the CKD group adjusted for multiple variables. Age (OR [95%CI]: 1.07, [1.06-1.09]), SBP (1.01, [1.00-1.01]), TG ≥150 mg/dL alone (1.34, [1.07-1.66]), TC ≥220 mg/dL alone (1.55, [1.23-1.94]), and high TG and TC (1.94, [1.48-2.54]) correlated with CKD. An additive effect of TG and TC on CKD was observed (data not shown). The synergistic effect of TG and TC on CKD was also noted in this regression model in another evaluation.
Figure 2 shows the OR of TC and TG in quartiles for CKD adjusted according to multiple variables. The lowest, second, third, and highest quartile ranges of total TC and TG were 0-166, 167-188, 189-212, and 213 mg/dL or higher and 0-71, 72-100, 101-148, and 149 mg/dL or higher, respectively. The OR of Q2 to Q4 of TC relative to Q1 for CKD increased linearly (OR [95%CI]: Q2, 1.3 [1.0-1.7]; Q3, 1.38 [1.1-1.8]; Q4, 1.5 [1.4-2.4]). Although the OR of Q2 and Q3 of TG for CKD did not increase, the OR of Q4 of TG for CKD was significantly higher than that for Q1 (OR [95% CI]: Q2, 0.95 [0.7-1.2]; Q3, 0.98 [0.8-1.2]; Q4, 1.21 [1.0-1.5]). The OR according to TG elevations significantly increased only in the highest quartile valued at 149 mg/dL or higher. The OR of Q4 with a TG level of 149 mg/dL or more was higher than that of Q1 to Q3 (OR [95% CI]: 1.24 [1.0-1.5]).