Relation of long-term body weight change to change in lipoprotein particle size in Japanese men and women: The INTERMAP Toyama Study

Objective: This study investigated the relationship between changes in lipoprotein particle size and body weight change over a 9-year period in Japanese adult men and women. Methods: Among 299 INTERMAP Toyama Study participants aged 40-59 in 1997, 260 were followed up in 2006 (129 men and 131 women). Their body weight and lipoprotein particle sizes were measured in 1997 and 2006. Nuclear Magnetic Resonance spectroscopy was used for the measurement of lipoprotein particle size. Results: The number of small LDL particles decreased from 774.3 to 617.4 nmol/L in men (p = 0.005) while the number increased from 353.2 to 414.5 nmol/L in women (p = 0.028) over this period. No significant changes in mean body weight were noted in either sex. Nine-year body weight change was positively associated with changes in the numbers of small LDL particles (men, r = 0.37, p < 0.001; women, r = 0.21, p = 0.018), but inversely associated with changes in LDL particle size (men, r = -0.30, p = 0.001; women, r = -0.16, p = 0.066) and HDL particle size (men, r = -0.42, p < 0.001; women, r = -0.42, p < 0.001). These relationships were similar even when adjusted for age, baseline body mass index, baseline values for LDL and HDL particle sizes, and other factors. The number of small LDL particles increased in both men and women in the body weight gain group. In the body weight loss group, the number of small LDL particles decreased in men but did not decrease in women. Conclusion: This 9-year observational study showed that the number and size of lipoprotein particles were strongly influenced by long-term body weight change.