The role of different lipid measures for incident hypertension during more than 12-year follow-up: Tehran Lipid and Glucose Study

The associations of different lipid measures and related indices with incident hypertension during a median follow-up of 12·89 years were examined. Fasting levels of total cholesterol (TC), TAG, HDL-cholesterol and LDL-cholesterol, and related indices (TC/HDL-cholesterol and TAG/HDL-cholesterol) were determined in 7335 Iranian adults (men = 3270) free of hypertension, aged 39·0 (sd 13·2) years. Multivariate Cox proportional hazard regression was applied and lipid parameters were considered either as categorical or continuous variables. During follow-up, 2413 (men = 1126) participants experienced hypertension. Using the first quartile as reference, significant trends were found between quartiles of TAG, HDL-cholesterol, TC/HDL-cholesterol and TAG/HDL-cholesterol in multivariate models; moreover considering these measures as continuous variables, a 1 sd increase in each of these parameters was significantly associated with the risk of incident hypertension; the corresponding hazard ratios and CI were 1·06 (95 % CI 1·02, 1·10), 0·94 (95 % CI 0·89, 0·98), 1·04 (95 % CI 1·01, 1·09) and 1·04 (95 % CI 1·01, 1·07), respectively. The associations between lipid measures and incident hypertension did not change after excluding lipid lowering drug users and those with type 2 diabetes mellitus and these associations were independent of the categories of baseline blood pressure (P for interaction > 0·08). These findings indicate that TAG, TAG/HDL-cholesterol and TC/HDL-cholesterol were independently associated with higher risk, while HDL-cholesterol was associated with lower risk of incident hypertension.

Association of different lipid measures with incident bone fractures: Tehran Lipid and Glucose Study

OBJECTIVE

to investigate the association between different lipid measures and long-term hospitalization-required incident fracture among Iranian men and women.

METHODS

A total of 3309 individuals aged ≥50 years (men = 1598) were included in the study. Multivariate Cox proportional hazard analyses were performed to assess the risk of incident fracture across quintiles, considering first quintile as reference, as well as for 1-standard deviation (SD) increase in each lipid measures i.e. total cholesterol (TC), triglycerides (TG), low and high density lipoprotein cholesterol (LDL-C and HDL-C, respectively), non-HDL-C, and related indices (TG/HDL-C and TC/HDL-C). Covariates included age, body mass index, current smoking, type 2 diabetes mellitus, hypertension, lipid lowering-drugs, and steroid medications (for women).

RESULTS

During a median follow-up of 18 years, incident fracture was observed in 201 cases (men=87). In both gender no linear association were found between different lipid measures and incident fracture. Among men only the fourth quartile of TG was associated with lower risk of fracture in the age adjusted analysis with hazard ratio (HR) and 95% confidence interval (CI) as [0.45 (0.21-0.95)]. Among women, the age-adjusted HRs and 95% CIs for the second, third, fourth and fifth quintiles of non-HDL-C were [0.46 (0.25-0.87)], [0.73 (0.42-1.25)], [0.90 (0.54-1.51)], [0.52 (0.29-0.95)], respectively; the corresponding values in the multivariate model, were [[0.48 (0.26-0.90)], [0.76 (0.4-1.32)], [0.94 (0.56-1.58)], and [0.52 (0.28-0.95)], respectively. The second quintile of LDL-C was also associated with lower risk for incident fracture in the multivariate analysis [0.53 (0.29-0.98)].

CONCLUSIONS

Among Iranian women a nonlinear association between non-HDL-C and LDL-C and incident fracture were found as the second and fifth quintile of the former and the second quintile of the latter were associated with about 50% lower risk of fracture .Generally our findings did not support harmful impact of these lipid measures on incident fracture.