Interaction between visceral adiposity and ambient air pollution on LDL cholesterol level in Korean adults

Although previous reports have found that obesity intensifies the negative impact of long-term air pollution exposure on the low-density lipoprotein-cholesterol (LDL-C) level, few studies have examined whether the type of abdominal adiposity, such as visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and the visceral-to-subcutaneous fat ratio (VSR) affects this relationship. We investigated the association between ambient air pollution and LDL-C in Korean adults and identified whether this association is different by the type of abdominal adiposity.

A total of 2737 adults were included. Abdominal fat areas were quantified by computed tomography, and the annual average concentration of air pollutants was included in this analysis.

In the total sample, none of the air pollutants was associated with LDL-C level in either the crude or adjusted model (all p > 0.05). The association was not significant even in subgroups stratified according to the obesity status defined by body mass index, and no interaction on the LDL-C level was also found (all p_int > 0.05). In the subgroup analysis stratified according to adiposity level, particulate matter with an aerodynamic diameter of ≤10 μm (PM₁₀) [β (SE) = 3.58 (1.59); p = 0.0245] and sulfur dioxide (SO₂) exposures [β (SE) = 2.71 (1.27); p = 0.0330] in the high-VAT group were associated with the increased LDL-C level. Interactions on LDL-C level were also found between VAT level and ambient air pollutants such as PM₁₀ and SO₂ (both p_int < 0.05). In the analysis of the VSR, PM₁₀ exposure showed a significant interaction on LDL level (p_int = 0.0032). However, the strength of these associations was not significant across all SAT subgroup (all p_int > 0.05).

In conclusion, we found that association between air pollution exposure and LDL-C level is different by abdominal fat distribution.