Familiality of triglyceride and LPL response to exercise training: The heritage study

Purpose: The main purpose of the present investigation was to test whether and to what extent familial/genetic factors are involved in the changes of postheparin lipoprotein lipase (ΔPH-LPL) activity and triglyceride (ΔTG) levels in response to exercise training. Additional hypotheses were also tested as to whether there were familial/genetic factors shared by baseline and the corresponding response to exercise training (i.e., by baseline triglyceride (TG(B)) and ΔTG and by baseline postheparin lipoprotein lipase (PH-LPL(B)) and ΔPH-LPL activity). Methods: Serum TG and PH-LPL were measured in 459 subjects from 99 sedentary Caucasian families of the HERITAGE Family study before (baseline) and after completing a 20 wk (3 times per week) exercise training protocol. The training protocol had a target intensity of 75% of the heart rate associated with baseline VO(2max) during the last 6 wk. PH-LPL activity was measured in the study subjects. Both univariate and bivariate familial correlation analyses were applied to the baseline and response data. Results: The maximal heritabilities for ΔTG and ΔPH-LPL activity were 22% and 15%, respectively. There were no common familial factors for TG(B) and ΔTG, nor were there any for PH-LPL(B) and ΔPH-LPL. However, we found that there were common familial factors underlying ΔTG and ΔPH-LPL; these familial factors seemed to differ across sex and generation groups. Conclusion: Although there were no common familial factors underlying the covariation between the baseline triglyceride and PH-LPL activity and the corresponding responses to exercise training (i.e., TG(B) with ΔTG or PH-LPL(B) with ΔPH-LPL), the ΔTG and ΔPH-LPL covariation apparently share some common familial determinants.