Seasonal exposure to phthalates and inflammatory parameters: A pilot study with repeated measures

Exposure to phthalates poses potential to damage multiple organs and system in the body. However, limited data are available regarding effects of seasonal exposure levels of phthalates and indicators reflecting inflammatory response. We designed a pilot study with repeated measures. We recruited 106 eligible habitants from Wuhan city, China. They completed questionnaires, physical examinations and provided urine specimens in winter and summer seasons. We found that urinary levels of low-molecular-weight phthalate metabolites were higher in summer than in winter (all P < 0.01). In winter, an interquartile range increase (1.264 μg/L) in 3-day moving average of high-molecular-weight phthalate metabolites corresponded to a 13.634% (95% CI: -22.331, -3.941) decrease in mean platelet volume, 25.879% (95% CI: -37.424, -12.204) for lymphocyte count or 10.862% (95% CI: -18.716, -2.125) for platelet count (P < 0.05 or P < 0.01). However, in summer, an interquartile range increase (1.215 μg/L) in urinary levels of high-molecular-weight phthalate metabolites corresponded to an 8.743% (95% CI: 4.217, 13.467) increase in platelet distribution width value or a 4.597% (95% CI: 2.335, 6.780) for mean platelet volume value at 3-day lag (both P < 0.01). In conclusion, phthalate exposure exhibited the potential for the activation of platelet function, particularly in winter. Seasonal variations of phthalate exposure should be considered when assessing health risk.