Gene environment interaction between phthalate exposure and pubertal genetic polymorphisms on blood pressure variability in children: Exploring the moderating effects of lifestyle behaviours

Phthalates (PAEs) are synthetic compounds extensively employed in consumer products. Blood pressure (BP) in children can vary, the degree of visit-to-visit BP variability (VVV) is at least partially independent of BP. The interactions between PAEs exposure, pubertal-related genetic susceptibility and lifestyles on childhood VVV are not investigated. This study utilized data from a cohort collected from Oct 2017-2020 in Xiamen, China. Seven urine PAE metabolites were measured. The long-term VVV was characterized employing the standard deviation (SD) and average real variability. We constructed a genetic risk score (GRS) of pubertal-related genes and healthy lifestyle scores. Exposed to high levels of mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) (OR=1.43, 95 %CI=1.07, 1.92) and mono-2-ethyl-5-oxohexyl phthalate (OR=1.36, 95 % CI=1.01, 1.83) was related to increased SBP-SD, and the OR for high SBP-SD related to high GRS was 1.38 (95 % CI=1.02, 1.85). Compared to participants who had low GRS and low MEHHP exposure, participants exhibiting high GRS and MEHHP levels were more likely to experience high SBP-SD (OR=2.00, P<0.05). Individuals exhibiting low GRS, low MEHHP levels, and adhering to healthy lifestyles were associated with the least probability of experiencing high SBP-SD (OR=0.31, P<0.05). Increased PAEs exposure could elevate childhood systolic VVV, and exacerbated the adverse impact of pubertal-related genetic susceptibility on the high VVV of SBP; however, healthy lifestyles might alleviate these adverse effects. Promoting healthy lifestyles and reducing PAEs exposure for preventing elevated BP variability among children is important, especially for individuals with greater genetic susceptibility to early pubertal onset. ENVIRONMENTAL IMPLICATION: Blood pressure (BP) in children can vary, as a noninvasive, inexpensive and applicable method, the extent of visit-to-visit variability (VVV) is at least partially independent of BP. The interactions between phthalates (PAEs) exposure, variants of puberty-related genes and lifestyles on VVV are not investigated. Increased childhood systolic VVV might be associated with PAEs exposure, with the associations more pronounced combined with pubertal genetic susceptibility. Yet, healthy habits could partly eliminate such adverse effects. Our study underscores the importance of advocating for healthy lifestyles and reducing exposure to PAEs, especially among individuals with high genetic susceptibility to early puberty onset.