Association of Blood Arsenic Concentrations with Lipid Markers in Uruguayan Adolescents: Exploring Effect Modification by Body Mass Index and Sex

= 327 in complete-case and 337 in imputed dataset) in Uruguay had blood As measured two times (T1 and T2), a year apart, during 2021-2023. Serum lipid markers were measured at T2. Blood As was averaged and log transformed. Separate linear regressions were built for each lipid marker. Analyses were stratified by sex and at 85th percentile of BMI to assess effect modification. Median (range) blood As at T1 and T2 were 0.38 (0.18, 4.01) µg/L and 0.36 (0.14, 4.81) µg/L, respectively. 8%, 25%, and 24% adolescents had borderline or high levels of TGL (> 150 mg/dL), TC (> 170 mg/dL), and non-HDLC (> 120 mg/dL), respectively, and 31% had low levels of HDL-C (< 45 mg/dL). Blood As showed a positive association with TGL [β (95% CI): 12.2 (0.88, 23.5)], but not other lipids. Blood As was positively associated with TGL [β (95% CI): 30.3 (8.24, 52.4)] among those with BMI≥85th percentile and with TC [12.4 (2.13, 22.6)], non-HDLC [12.0 (2.81, 21.1)] and TGL [20.3 (5.17, 35.4)] among girls. Similar findings were seen in the complete case and imputed datasets. Our study showed that low-level blood As was associated with higher TGL levels among Uruguayan adolescents with evidence of an interaction with BMI and sex. Supplementary Information: The online version contains supplementary material available at 10.1007/s12403-026-00768-x.