A negative association between blood lead level (BPbL) and vitamin D metabolites in occupationally exposed populations has been reported but data from the general population are scarce. Furthermore, the association between BPbL and vitamin D binding protein (DBP) and free 25-hydroxyvitamin D [25(OH)D] has not been reported. We investigated the association of BPbL with DBP, total and free 25(OH)D in healthy adolescents (N=1347; age range 11-16 years) cross-sectionally selected from all Governorates of Kuwait, utilizing multi-stage cluster random sampling. Pb in whole blood was analyzed by inductively coupled plasma mass spectrometry, and DBP with ELISA. Plasma 25(OH)D was analyzed by LC-MS/MS and free 25(OH)D was calculated utilizing the levels and binding affinities of DBP and albumin for 25(OH)D. DBP was positively associated with BPbL [β (95%CI)= 0.81 (0.14 −0.22); p< 0.001]. A negative association between BPbL and total 25(OH)D was non-significant (p=0.24) when BPbL was used as continuous variable but was significant when used as quartiles (p=0.02). The negative association between BPbL and free 25(OH)D was significant whether BPbL was used as continuous, as quartiles or as cut-off point of <5µg/dL. In multinomial logistic regression, the odds of vitamin D insufficiency and deficiency were more than two-fold higher in the upper quartiles of BPbL compared to the lowest quartile. The negative correlation of BPbL with free 25(OH)D was more robust than its correlation with total 25(OH)D. Future studies must consider the levels of DBP when assessing the association between Pb and vitamin D metabolites.

Background Elevated blood lead level (EBLL) is a public health problem in both developing and industrialized countries. Being a petrochemical-based economy, lead (Pb) levels are expected to be high in Kuwait, but systematic data on population exposure are lacking. This study aimed at determining the prevalence of EBLL in adolescents in Kuwait. Methods Adolescents (N = 1385; age range 11–16 years) were cross-sectionally selected from public middle schools from all Governorates of Kuwait, utilizing multistage cluster random sampling. Pb in whole blood was analyzed by inductively coupled plasma mass spectrometry. Distribution of blood Pb levels (BLL) among Governorates and sexes were compared by non-parametric tests and the prevalence of EBLL (defined as BLL above the CDC reference level of ≥5 μg/dL) was estimated by χ2 test. Binary logistic regression was used for assessing the association between EBLL and Governorate. Results Median (IQR) BLL was 5.1(3.6–7.1) μg/dL [4.9 (3.8–6.5) μg/dL in males and 5.4 (3.3–7.6) μg/dL in females; p = 0.001]. In the overall sample, 51% had BLL ≥5 μg/dL; 13% had ≥10 μg/dL and 3% > 20 μg/dL. Prevalence of EBLL was 47% in males and 56% in females (p < 0.001). EBLLs were clustered in Al-Asima, Al-Ahmadi (in both sexes); Al-Jahra (in males) and Mubarak Al-Kabeer (in females) Governorates. Conclusions EBLL is a significant public health problem in adolescents in Kuwait. Urgent public health intervention is required in areas with EBLL, and the sources of exposure need to be identified for prevention.

Background: Environmental lead (Pb) exposure is a public health problem in many developing and industrialized countries. Being a petrochemical industry-based economy, Pb levels are expected to be high in Kuwait but systematic data on population exposure are lacking. This study aimed at determining the prevalence of Pb toxicity in adolescents in Kuwait.Methods: Adolescents (N=1385; age range 11-16 years) were cross-sectionally selected from public middle schools from all Governorates of Kuwait, utilizing multi-stage cluster random sampling. Pb in whole blood was analyzed by inductively coupled plasma mass spectrometry. Pb levels among Governorates and genders were compared by median test and the prevalence of Pb levels above the CDC cutoff (≥5 µg/dL) was estimated by x2 test. Multiple logistic regression was used for association between prevalence of high Pb levels and Governorate.Results: Median (IQR) Pb was 5.1(3.6 – 7.1) µg/dL [4.9 (3.8 6.5) µg/dL in males and 5.4 (3.3-7.6) µg/dL in females; p=0.001]. In the overall sample, 51% had Pb levels ≥5 µg/dL; 13% were ≥10 µg/dL and 3% >20 µg/dL. Prevalence of Pb ≥5 µg/dL was 47% in males and 56% in females (p<0.001). High Pb levels were clustered in Al-Asima and Al-Ahmadi (in both genders); Al-Jahra (in males) and Mubarak Al-Kabeer (in females) Governorates.Conclusion: Pb exposure is a significant public health problem in adolescents in Kuwait. Urgent public health intervention is required in high Pb exposure areas and further research is needed to identify the sources of exposure in these areas for prevention.