Associations between blood lead level and substance use and sexually transmitted infection risk among adults in the United States

Association between human papillomavirus vaccine status and sexually transmitted infection outcomes among females aged 18-35 with a history of sexual activity in the United States: A population survey-based cross-sectional analysis

BACKGROUND

Current human papillomavirus (HPV) vaccine coverage in the United States (in 2019, 66-70%), remains below the Healthy People 2020 coverage goal of 80%. HPV vaccine misinformation, including parental concerns of sexual risk-compensation influence vaccine uptake. We examined the association between HPV vaccination and sexually transmitted infection (STI) outcomes.

METHODS

Of the 20,146 participants from 2013 to 2014 and 2015-2016 cycles of the National Health and Nutrition Examination Survey, 1050 females aged 18-35 with a history of sexual activity had complete case data. Roa-Scott Chi-squared and F-tests assessed survey-weighted socio-demographic differences between vaccinated and unvaccinated participants. Weighted logistic regression assessed crude and adjusted associations between self-reported HPV vaccination (none vs. ≥ 1dose) and lab-confirmed STIs (trichomonas and chlamydia) and vaccine-type HPV (6/11/16/18). As a sensitivity analysis, we conducted weighted-propensity score (PS) models and inverse probability weighting by vaccination status. PS and logistic regression were estimated through survey-weighted logistic regression on variables including race, education, income, marital status, US citizenship, cycle year and age.

RESULTS

Overall, 325 (31.8%) females with a history of sexual activity were HPV vaccinated, of which 22 (6.1%) received the vaccine at the routine-recommended ages of 11-12, 65.7% were vaccinated after their self-reported sexual debut, 3.8% had a lab-confirmed STI and 3.5% had vaccine-type HPV. There was no association between HPV vaccination and any STIs (adjusted odds ratio [aOR] 0.67, 95%CI:0.38-1.20), and vaccinated participants had 61% reduced odds of vaccine-type HPV (vs. unvaccinated; aOR 0.39, 95%CI:0.19-0.83). Results from the PS sensitivity analysis were similar to the main findings.

CONCLUSION

Among females who reported a history of sexual activity, HPV vaccination status was protective against vaccine-type HPV and not associated with lab-based STI outcomes. Although findings may be susceptible to reporting bias, results indicating low vaccine uptake at routine-recommended ages requires additional efforts promoting HPV vaccination before sexual-debut.

A review of the evidence to support interim reference level for dietary lead exposure in adults

FDA developed the interim reference level (IRL) for lead of 3 μg/day in children and 12.5 μg/day in women of childbearing age (WOCBA) to better protect the fetus from lead toxicity. These IRLs correspond to a blood lead level (BLL) of 0.5 μg/dL in both populations. The current investigation was performed to determine if the IRL for WOCBA should apply to the general population of adults. A literature review of epidemiological studies was conducted to determine whether a BLL of 0.5 μg/dL is associated with adverse effects in adults. Some studies reported adverse effects over a wide range of BLLs that included 0.5 μg/dL adding uncertainty to conclusions about effects at 0.5 μg/dL; however, no studies clearly identified this BLL as an adverse effect level. Results also showed that the previously developed PTTDI for adults of 75 μg/day lead may not be health protective, supporting use of a lower reference value for lead toxicity in this population group. Use of the 12.5 μg/day IRL as a benchmark for dietary lead intake is one way FDA will ensure that dietary lead intake in adults is reduced.

Dose-response relationship between blood lead levels and hematological parameters in children from central China

BACKGROUND

Lead is a heavy metal that can affect the human hematological system. However, reports are limited on the dose-response relationship between blood lead levels (BLLs) and hematological parameters in children. This study aimed to explore the dose-response relationship between BLLs and hematological measurements among children in China.

METHODS

A cross-sectional design was used. A total of 743 children aged 5-8 years were recruited from two counties in central China. The BLLs and blood levels of iron, zinc, and calcium were determined, and hematological parameters were measured.

RESULTS

All hematological measurements and BLLs were logarithm-transformed to ensure a normal distribution. The geometric mean of the BLLs of all children was 82.4 μg/L. Forty-one percent of the children had BLLs ≥ 100 μg/L. The lead-poisoning percentages of the children were significantly associated with gender, age, district of residence, and environmental lead exposure level. Multivariate linear regression analyses showed no significant linear correlation between BLL and each hematological parameter among the children with BLLs ≥ 100 μg/L. The analyses also revealed a small increase in red blood cell count (RBC) with increasing BLLs in the BLLs < 100 μg/L group (β = 0.03, P =  0.048). A negative association was noted between BLLs and blood platelet (PLT) count in the children with BLLs < 100 μg/L (β = -0.90, P < 0.001). Logistic regression analyses showed that BLLs were significantly associated with decreased hemoglobin (Hb) levels, RBC counts, PLT counts and mean corpuscular hemoglobin (MCH) after adjusting for potential confounders. Such analyses also revealed a dose-response relationship between the BLLs and hematological parameters (Hb level, RBC count, and PLT count). The children with BLLs ≥ 100 μg/L were 2.72, 2.51, and 3.76 times more likely to achieve decreased RBC counts, Hb levels and PLT counts, respectively, compared to those with BLLs < 100 μg/L. Compared with children with BLLs < 100 μg/L, those with BLLs ≥ 100 μg/L were 3.16 and 4.38 times more likely to show decreased Hb levels and PLT counts respectively in the high-level lead-exposure group and 4.33 times more likely to achieve a decreased PLT count in the low-level lead-exposure group. The individuals with BLLs of the highest quartile were 3.65, 5.87, and 29.23 times more likely to exhibit decreased Hb levels, RBC counts, and PLT counts, respectively, than the children with BLLs of the lowest quartile.

CONCLUSION

Our findings suggested a negative association between BLLs and hematological indicators (Hb level, RBC count, PLT count and MCH). A strong negative, non-linear dose-response relationship was also showed between BLLs and hematological parameters (Hb level, RBC count, and PLT count).

Age of first drunkenness and risks for all-cause mortality: A 27-year follow-up from the epidemiologic catchment area study

BACKGROUND

Early-onset drunkenness is associated with an increased risk of developing an alcohol use disorder (AUD), which predicts excess mortality risk. Here, we estimated mortality risk for drinkers with and without early drunkenness.

METHODS

For 14,848 adult participants interviewed about drinking, drunken episodes, and AUD in 1981-83 for the Epidemiologic Catchment Area in New Haven (Connecticut), Baltimore (Maryland), St. Louis (Missouri), and Durham (North Carolina), we linked National Death Index records through 2007.

RESULTS

Cox regression modeling estimates showed excess mortality for drinkers with age of first drunkenness earlier than 15 years old (hazard ratio, HR: 1.47, 95% CI: 1.25, 1.72) and when first drunkenness occurred at or after age 15 (HR: 1.20, 95% CI: 1.11, 1.29), as compared with adults who had never been drunk. Consistent results were observed, irrespective of AUD history. That is, early drunkenness signaled excess mortality risk even in absence of AUD.

CONCLUSIONS

In a large community sample from four cities in the US, early age of onset of drunkenness predicts mortality risk. We discuss experiments to investigate the possible causal significance of this predictive association.

Trends and variability in blood lead concentrations among US adults aged 20-64 years and senior citizens aged ≥65 years

Using data from National Health and Nutrition Examination Survey for the period 2003-2012, the objective of this study was to evaluate trends in blood lead levels (BLL) among adults aged 20-64 years (adults) and seniors aged ≥65 years (seniors). In addition, the contribution of other factors like gender, race/ethnicity, smoking, and exposure to secondhand smoke at home in explaining variability in BLL was also evaluated by fitting regression models with log10 transformed values of BLL as dependent variables. BLL decreased over 2003-2012 (p < 0.01). Irrespective of gender, race/ethnicity, and smoking status, seniors were found to have higher BLL than adults. Based on the magnitude of differences between the 5th and 95th percentiles, variability in the levels of blood lead was found to be substantially higher among seniors than among adults. Males had statistically significantly higher adjusted BLL than females (2.32 vs. 1.76 μg/dL for seniors, p < 0.01 and 1.66 vs. 1.13 μg/dL for adults, p < 0.01). Non-Hispanic whites had statistically significantly lower adjusted BLL than non-Hispanic blacks (1.99 vs. 2.42 μg/dL for seniors, p < 0.01 and 1.22 vs. 1.42 μg/dL for adults, p < 0.01). When compared with non-smokers, smokers had statistically significantly higher BLL (2.19 vs. 1.86 μg/dL for seniors, p < 0.01 and 1.54 vs. 1.22 μg/dL for adults, p < 0.01). Non-obese had statistically significantly higher BLL than obese individuals (2.11 vs. 1.93 μg/dL for seniors, p < 0.01 and 1.48 vs. 1.27 μg/dL for adults, p < 0.01). Exposure to secondhand smoke at home (SHS) was associated with statistically significantly higher BLL than when there was no exposure to SHS (β = 0.0683, p = 0.03 for seniors; β = 0.034, p = 0.034, p < 0.01 for adults).

Trends and variability in blood lead concentrations among US children and adolescents

Using data from the National Health and Nutrition Examination Survey for the period 2003-2012, the objective of this study was to evaluate trends in blood lead levels (BLL) among children aged 1-5 and 6-11 years and smoker and nonsmoker adolescents aged 12-19 years. Regression models with log10 transformed values of BLLs as dependent variable were fitted to evaluate how gender, race/ethnicity, smoking, and exposure to secondhand smoke at home affect BLLs. Irrespective of age, gender, and race/ethnicity, BLLs declined over the study period (p ≤ 0.01). Overall, adjusted BLLs declined by 0.00114 μg/dL for every 2 years. Children aged 1-5 years had about 50 % higher BLLs than smoker adolescents, about 75 % higher BLLs than nonsmoker adolescents, and about 45 % higher BLLs than children aged 6-11 years. While overall, children aged 1-5 years with BLL ≥ 5 μg/dL made up 3.24 %, 7.8 % non-Hispanic Black children aged 1-5 years had BLL ≥ 5 μg/dL. Males were found to have higher adjusted BLLs than females, and non-Hispanic Blacks were found to have higher adjusted BLLs than non-Hispanic Whites. Higher poverty income ratio was associated with lower adjusted BLLs (β = -0.02916, p < 0.01). Children living in owner-occupied homes had lower adjusted BLLs than children living in renter-occupied homes. BLLs increased with increase in number of smokers smoking inside the home (β = 0.02496, p = 0.02). In conclusion, while BLLs have declined for all age groups, genders, and races/ethnicities, certain races/ethnicities like non-Hispanic Blacks continue to have substantially higher BLLs than non-Hispanic Whites.

Elevated blood lead and cadmium levels associated with chronic infections among non-smokers in a cross-sectional analysis of NHANES data

BACKGROUND

Experimental animal studies, in vitro experiments, and clinical assessments have shown that metal toxicity can impair immune responses. We analyzed data from a United States representative National Health and Nutrition Examination Survey (NHANES) to explore associations between chronic infections and elevated blood concentrations of lead and cadmium among non-smoking NHANES participants.

METHODS

NHANES data from 1999 to 2012 were examined and weighted to represent the United States population. Multivariable logistic regression was used to estimate adjusted odds ratios (AOR) and 95 % confidence intervals (CI) for heavy metal associations with seropositivity for Helicobacter pylori, Toxoplasma gondii, and Hepatitis B virus (HBV) infections.

RESULTS

Available 2-year survey cycles for infection seroprevalence varied by pathogen, from 1 to 7 cycles. Available sample size, disease seroprevalence, and participant age range also varied by pathogen of interest. After controlling for demographic characteristics and general health condition, an elevated blood lead level above the survey population median was significantly associated with seropositivity for all three pathogens (AORs = 1.2-1.5). In addition, an elevated blood cadmium level above the median was significantly associated with HBV (AOR = 1.5; 95 % CI = 1.2-2.0) and H. pylori (AOR = 1.5; 95 % CI = 1.2-1.7) seropositivity. Age-specific analyses for H. pylori and T. gondii indicated stronger associations among children under 13 years of age, particularly for lead exposure and H. pylori seropositivity, and weaker associations among those over 35 years of age.

CONCLUSIONS

The results of this cross-sectional human health survey suggest that the immunological effects of lead and cadmium toxicity may be associated with an increased susceptibility to chronic infections.