[Follow-up study on the effects of lipid ratios on all-cause mortality among elderly adults in longevity areas of China].

OBJECTIVE

To explore the association between lipid ratios and all-cause mortality among elderly adults aged 80 years and older living in longevity areas of China.

METHODS

A total of 874 participants in the Chinese Longitudinal Healthy Longevity Survey during June 2009 were included in our baseline survey. Lipid concentrations were measured and lipid ratios including LDL-C/HDL-C, TG/HDL-C, and atherosclerosis index (AI) were calculated at baseline, and the information on questionnaires, body measurement, and blood biochemical profiles was collected. Survival time and survival status were followed up in August 2012. Subjects were stratified into three groups (low, middle and high) by tertiles of lipid ratios. All-cause mortality was calculated. Cox regression models were used to assess the association of lipid ratios with mortality.

RESULTS

During 38 months of follow-up, a total of 427 participants had died, 378 participants survived, and 69 participants were lost to follow-up; overall mortality was 50.5%. For these participants, P50 (P25-P75) values for LDL-C/HDL-C were 1.68 (1.22-2.05), 1.85 (1.34-2.16), and 1.78 (1.33-2.08), respectively (H=6.93, P=0.025); values for TG/HDL-C were 1.00 (0.79-1.34), 1.20 (0.97-1.53), and 1.23 (0.95-1.72), respectively (H=9.18, P=0.008). AIs were 2.12 (1.72-2.61), 2.27 (1.84-2.75), and 2.13 (1.80-2.58), respectively (H=6.37, P=0.041). Values for 38-month all-cause mortality were 53.1%, 50.0%, and 44.0% among participants with low, middle, and high LDL-C/HDL-C ratios (<1.39, 1.39-1.92, ≥1.92), respectively (χ(2)=7.54, P=0.024); these values were 54.8%, 46.4%, and 45.3% among participants with low, middle, and high AIs (<1.83, 1.83-2.39, ≥2.39), respectively (χ(2)=6.67, P=0.035). Each 1 unit increase of LDL-C/HDL-C, TG/HDL-C , and AI corresponded to a 17%, 15%, and 13% decrease in 38-month all-cause mortality, respectively; adjusted HRs were 0.83 (0.72-0.97), 0.85 (0.74-0.99), and 0.87 (0.76-0.99), respectively. Compared with participants who had low LDL-C/HDL-C ratios, high ratios were associated with lower risk of mortality (HR 0.88; (95% CI: 0.78-0.99)). Compared with low AIs, middle and high values were associated with lower risk of mortality HRs (95%CI) were 0.84 (0.72-0.98) and 0.87 (0.78-0.98);respectively.

CONCLUSION

LDL-C/HDL-C, TG/HDL-C, and AI were negatively associated with all-cause mortality among elderly adults aged 80 years and older living in longevity areas of China.