Association of tobacco smoke exposure with metabolic profile from childhood to early adulthood: the Special Turku Coronary Risk Factor Intervention Project

AIMS

To investigate the associations between passive tobacco smoke exposure and daily smoking with a comprehensive metabolic profile, measured repeatedly from childhood to adulthood.

METHODS AND RESULTS

Study cohort was derived from the Special Turku Coronary Risk Factor Intervention Project (STRIP). Smoking status was obtained by questionnaire, while serum cotinine concentrations were measured using gas chromatography. Metabolic measures were quantified by nuclear magnetic resonance metabolomics at 9 (n = 539), 11 (n = 536), 13 (n = 525), 15 (n = 488), 17 (n = 455), and 19 (n = 409) years. Association of passive tobacco smoke exposure with metabolic profile compared participants who reported less-than-weekly smoking and had serum cotinine concentration <1 ng/mL (no exposure) with those whose cotinine concentration was ≥10 ng/mL (passive tobacco smoke exposure). Associations of daily smoking with metabolic profile in adolescence were analysed by comparing participants reporting daily smoking with those reporting no tobacco use and having serum cotinine concentrations <1 ng/mL. Passive tobacco smoke exposure was directly associated with the serum ratio of monounsaturated fatty acids to total fatty acids [β = 0.34 standard deviation (SD), (0.17-0.51), P < 0.0001] and inversely associated with the serum ratios of polyunsaturated fatty acids. Exposure to passive tobacco smoke was directly associated with very-low-density lipoprotein particle size [β = 0.28 SD, (0.12-0.45), P = 0.001] and inversely associated with HDL particle size {β = -0.21 SD, [-0.34 to -0.07], P = 0.003}. Daily smokers exhibited a similar metabolic profile to those exposed to passive tobacco smoke. These results persisted after adjusting for body mass index, STRIP study group allocation, dietary target score, pubertal status, and parental socio-economic status.

CONCLUSION

Both passive and active tobacco smoke exposures during childhood and adolescence are detrimentally associated with circulating metabolic measures indicative of increased cardio-metabolic risk.

Covariation between serum cotinine and blood lead levels among US pediatric populations: Trends from 1999 to 2018

BACKGROUND

Tobacco smoke, including both active and passive smoke, can be an important source of lead exposure. However, the relationship between passive tobacco smoke exposure (PTSE) and blood lead levels (BLL), especially in vulnerable populations, needs to be further explored. The present study was to assess the covariation between serum cotinine, a measure of PTSE, and BLL in a pediatric population during 1999-2018.

METHODS

Data on 21,817 children, aged 3-19 years, was extracted from the biennial nationally representative surveys. The trends of the prevalence of lead exposure (BLL ≥ 3.5 µg/dL) and PTSE (cotinine ≥ 1 ng/mL but < 10 ng/mL) were determined, and the covariation between BLL and cotinine was assessed. The population attributable fraction (PAF) of PTSE to the BLL was proxied using the partial R2 of the hierarchical linear regression. The association between PTSE and lead exposure was estimated using multivariate logistic regression.

RESULTS

A parallel decreasing trend in the prevalence of lead exposure and PTSE was observed. Similarly, the means of both BLL and cotinine declined simultaneously. Overall, the PAF from PTSE towards blood lead was 7 %, doubling the PAF from race/ethnicity and family income combined. Stratified by race/ethnicity, PAF from PTSE was 8 % in Blacks and Whites and 4 % for Hispanics. The odds ratio of PTSE with lead exposure was 2.45 (95 % CI, 1.75, 3.44), 2.00 (1.21, 3.33), and 1.16 (0.64, 2.13) for Black, White, and Hispanic children, respectively. Cotinine mean remained two times higher in Blacks than non-Black children at the end of the study period.

CONCLUSION

Serum cotinine and BLL may have a significant association in children that persists even as both have been steadily declining in recent years. The contribution from PTSE to blood lead variations could be greater than that from socioeconomic factors. Further reducing lead exposure might be achieved by eliminating PTSE, particularly for the Black pediatric population.