Association between Blood Lead and Walking Speed in the National Health and Nutrition Examination Survey (NHANES 1999–2002)

Background: Walking speed is a simple and reliable measure of motor function that is negatively associated with adverse health events in older people, including falls, disability, hospital admissions, and mortality. Lead has adverse affects on human health, particularly on the vascular and neurological systems.Objective: We explored the hypothesis that lead is associated with slower walking speed.Methods: We used U.S. National Health and Nutrition Examination Survey (NHANES) cross-sectional data from 1999–2002. The time to walk 20 ft (walking speed) was measured among 1,795 men and 1,798 women ≥ 50 years of age. The association between walking speed and quintiles of blood lead concentration was estimated separately in men and women using linear regression models adjusted for age, education, ethnicity, alcohol use, smoking status, height, and waist circumference.Results: Mean blood lead concentrations and walking speeds were 2.17 μg/dL and 3.31 ft/sec in women, and 3.18 μg/dL and 3.47 ft/sec in men, respectively. Among women, walking speed decreased with increasing quintiles of blood lead, resulting in an estimated mean value that was 0.11 ft/sec slower (95% CI: –0.19, –0.04; p-trend = 0.005) for women with blood lead concentrations in the highest versus lowest quintile. In contrast, lead was not associated with walking speed in men.Conclusion: Blood lead concentration was associated with decreased walking speed in women, but not in men. Our results contribute to the growing evidence that lead exposure, even at low levels, is detrimental to public health.     

Association between objectively-measured physical activity and sleep,NHANES 2005–2006

Statement of problemEpidemiological studies examining the association between physical activity and sleep have relied on self-report measures of physical activity and have primarily been conducted in older adults. Therefore, to address these gaps in the literature, the purpose of the present study was to examine the association between objectively-measured physical activity and a variety of self-reported sleeping parameters in a nationally representative sample of U.S. adults of all ages.MethodsData from the National Health and Nutrition Examination Survey (NHANES) 2005–2006 were used in the analyses. 3081 adults ranging in age between 18 and 85 were included in the analyses. At the mobile examination center, participants were asked to wear an ActiGraph 7164 accelerometer on the right hip for 7 days following their examination. Questions on sleep were asked during the household interview.ResultsAfter controlling for age, bmi, health status, smoking status, and depression, the relative risk of often feeling overly sleepy during the day compared to never feeling overly sleepy during the day decreased by a factor of 0.65 (95% CI: 0.44–0.97) for participants meeting physical activity guidelines compared to those not meeting guidelines. Similar results were also found for having leg cramps while sleeping and having difficulty concentrating when tired.ConclusionsObjectively-measured physical activity was associated with several self-reported sleeping-related parameters. Future experimental studies are required to confirm that increasing physical activity causes improvements in these parameters.     

Air Lead Exposures and Blood Lead Levels within a Large Automobile Manufacturing Workforce, 1980–1985

Recent (1980–1985) trends in air lead (PbA) exposures and blood lead (PbB) levels experienced by approximately 10 000 workers employed in various stages of the automobile manufacturing process (i.e., auto assembly, lead-acid battery manufacture, foundry work, and “other” manufacturing-related operations) are described. Between 1980–1985, the mean PbB levels of assembly, battery, foundry, and “other” workers decreased by 28, 24, 3, and 27%, respectively, to 16.6, 23.6, 15.9, and 11.8 μg Pb/dl. Workers in the following job categories experienced the highest annual mean PbB levels: paste machine operators (battery plants), solder-grinders (assembly plants), and crane operators (foundries). During the same period, median 8-h Time Weighted Average PbA exposures (μg Pb/m³) in assembly plants, battery plants, and foundries decreased by 10, 12, and 20%, respectively, to 8.1, 13.6, and 10.9 μg/m³.     

Elevated Blood Lead Levels Among Fire Assay Workers and Their Children in Alaska, 2010–2011

In October 2010, an employee at Facility A in Alaska that performs fire assay analysis, an industrial technique that uses lead-containing flux to obtain metals from pulverized rocks, was reported to the Alaska Section of Epidemiology (SOE) with an elevated blood lead level (BLL) ≥10 micrograms per deciliter (μg/dL). The SOE initiated an investigation; investigators interviewed employees, offered blood lead screening to employees and their families, and observed a visit to the industrial facility by the Alaska Occupational Safety and Health Section (AKOSH). Among the 15 employees with known work responsibilities, 12 had an elevated BLL at least once from October 2010 through February 2011. Of these 12 employees, 10 reported working in the fire assay room. Four children of employees had BLLs ≥5 μg/dL. Employees working in Facility A''s fire assay room were likely exposed to lead at work and could have brought lead home. AKOSH inspectors reported that they could not share their consultative report with SOE investigators because of the confidentiality requirements of a federal regulation, which hampered Alaska SOE investigators from fully characterizing the lead exposure standards.Occupational lead exposure continues to threaten workers'' health.^1–3 In the United States, the Occupational Safety and Health Administration (OSHA) prescribes standards for permissible exposure limits for lead in the workplace and specifies that a blood lead level (BLL) of 40 micrograms per deciliter (μg/dL) triggers more frequent (i.e., every two months rather than every six months) blood lead testing. OSHA standards require that workers with a BLL ≥60 μg/dL, or an average BLL for the last three tests or all tests during the previous six months (whichever is longer) of ≥50 μg/dL, be removed from the lead exposure area, unless the most recent test indicated a BLL ≤40 μg/dL.⁴ However, research has increased concern regarding lead toxicity at lower doses and has supported a reevaluation of the level at which BLLs can be considered safe.⁵ The National Institute for Occupational Safety and Health (NIOSH) defines an elevated BLL in an adult as ≥10 μg/dL.⁶ In addition to adverse impacts on the health of the workers themselves, children of lead-exposed workers have disproportionately higher BLLs when compared with other children.^7–9Elevated BLLs among adults are associated with muscle and joint pain, reproductive problems, and neurologic symptoms, including memory loss.¹⁰ Negative health effects have been observed among adults with only modestly elevated BLLs,^11–13 with increased odds of an ill effect occurring at levels as low as 1.6–2.4 μg/dL.¹¹ Among children, elevated BLLs can result in devastating health effects, including brain and nervous system damage, slow growth, and hearing problems.¹⁰ Research indicates that there is no safe level of lead among children.¹⁴ Despite considerable data on the deleterious health effects of lead regarding both children and adults, harmful occupational exposures that are inadequately controlled continue to put workers and their families at risk. A BLL of ≥5 μg/dL is the reference level that the Advisory Committee on Childhood Lead Poisoning Prevention has recommended to identify children with elevated BLLs.¹⁴ Elevated BLLs ≥10 μg/dL for children and adults are reportable in Alaska under Alaska Administrative Code 27.014.¹⁵     

The Influence of Declining Air Lead Levels on Blood Lead–Air Lead Slope Factors in Children

Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient air lead (PbA), given the multitude of lead (Pb) sources and pathways of exposure. The PbB–PbA relationship has previously been evaluated across populations. This relationship was a central consideration in the 2008 review of the Pb national ambient air quality standards.Objectives: The objectives of this study were to evaluate the relationship between PbB and PbA concentrations among children nationwide for recent years and to compare the relationship with those obtained from other studies in the literature.Methods: We merged participant-level data for PbB from the National Health and Nutrition Examination Survey (NHANES) III (1988–1994) and NHANES 9908 (1999–2008) with PbA data from the U.S. Environmental Protection Agency. We applied mixed-effects models, and we computed slope factor, d[PbB]/d[PbA] or the change in PbB per unit change in PbA, from the model results to assess the relationship between PbB and PbA.Results: Comparing the NHANES regression results with those from the literature shows that slope factor increased with decreasing PbA among children 0–11 years of age.Conclusion: These findings suggest that a larger relative public health benefit may be derived among children from decreases in PbA at low PbA exposures. Simultaneous declines in Pb from other sources, changes in PbA sampling uncertainties over time largely related to changes in the size distribution of Pb-bearing particulate matter, and limitations regarding sampling size and exposure error may contribute to the variability in slope factor observed across peer-reviewed studies.Citation: Richmond-Bryant J, Meng Q, Davis A, Cohen J, Lu SE, Svendsgaard D, Brown JS, Tuttle L, Hubbard H, Rice J, Kirrane E, Vinikoor-Imler LC, Kotchmar D, Hines EP, Ross M. 2014. The Influence of declining air lead levels on blood lead–air lead slope factors in children. Environ Health Perspect 122:754–760; http://dx.doi.org/10.1289/ehp.1307072     

Association between urinary cadmium levels and prediabetes in the NHANES 2005–2010 population

Evidence suggests an association between exposure to cadmium and dysglycemia. To investigate this matter, we examined the relationship between urinary cadmium and prediabetes in the cross sectional National Health and Nutrition Examination Survey (NHANES). NHANES participants for the years 2005 through 2010 aged ≥40 years were included in the analysis. Participants with nephropathy, overt diabetes, or missing required data were excluded. To assess the non-linear relationship between cadmium and Prediabetes, non-parametric logistic regression with B spline expansion of urinary cadmium/creatinine ratio was performed. This analysis revealed a complex non-linear association between higher cadmium levels and prediabetes. This relationship persisted, though with varying magnitudes across smoking groups (never smokers, moderate smokers, heavy smokers). In a conventional logistic regression analysis, this relationship was less evident with significantly increased OR for prediabetes was found in the highest quintile of urine cadmium compared to the lowest quintile in the overall population and in moderate smokers. In an age stratified analysis, a significant linear association was found only in the age groups 60–69 and ≥70. We conclude that there is a significant non-linear, complex relationship between urinary Cd levels, age, smoking habits and odds of prediabetes.     

Environmental Pollution and Blood Lead Levels in Nigeria: Who is Unexposed?

Abstract

While blood lead levels (BLLs) in many western countries have progressively declined since 1976, in Nigeria high BLL continue to be documented not only in exposed workers but also in "unexposed" control subjects. The problem of environmental lead exposure has hitherto gone unaddressed by both researchers and health policy makers in Nigeria despite the immense public health importance. Continued high BLLs in Nigeria cast doubt on researchers' ability to find real "unexposed control subjects" in future studies, and point to the importance of controlling environmental lead exposures.     

Association of Perfluoroalkyl Substances,Bone Mineral Density,and Osteoporosis in the U.S. Population in NHANES 2009–2010

Background

Perfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA), are detectable in the serum of 95% of the U.S. population.

Objective

Considering the role of PFASs as endocrine disruptors, we examined their relationships with bone health.

Methods

The association between serum PFAS concentration and bone mineral density at total femur (TFBMD), femoral neck (FNBMD), lumbar spine (LSBMD), and physician-diagnosed osteoporosis was assessed in 1,914 participants using data from the National Health and Nutritional Examination Survey 2009–2010.

Results

The mean age of the participants was 43 years. Men had higher serum PFAS concentrations than women (p < 0.001) except for PFNA. In both sexes, serum PFOS concentrations were inversely associated with FNBMD (p < 0.05). In women, significant negative associations were observed for natural log (ln)–transformed PFOS exposure with TFBMD and FNBMD, and for ln-transformed PFOA exposure with TFBMD (p < 0.05). In postmenopausal women, serum PFOS was negatively associated with TFBMD and FNBMD, and PFNA was negatively associated with TFBMD, FNBMD, and LSBMD (all p < 0.05). With one log unit increase in serum PFOA, PFHxS, and PFNA, osteoporosis prevalence in women increased as follows: [adjusted odds ratios (aORs)] 1.84 (95% CI: 1.17, 2.905), 1.64 (95% CI: 1.14, 2.38), and 1.45 (95% CI: 1.02, 2.05), respectively. In women, the prevalence of osteoporosis was significantly higher in the highest versus the lowest quartiles of PFOA, PFHxS, and PFNA, with aORs of 2.59 (95% CI: 1.01, 6.67), 13.20 (95% CI: 2.72, 64.15), and 3.23 (95% CI: 1.44, 7.21), respectively, based on 77 cases in the study sample.

Conclusion

In a representative sample of the U.S. adult population, serum PFAS concentrations were associated with lower bone mineral density, which varied according to the specific PFAS and bone site assessed. Most associations were limited to women. Osteoporosis in women was also associated with PFAS exposure, based on a small number of cases.

Citation

Khalil N, Chen A, Lee M, Czerwinski SA, Ebert JR, DeWitt JC, Kannan K. 2016. Association of perfluoroalkyl substances, bone mineral density, and osteoporosis in the U.S. population in NHANES 2009–2010. Environ Health Perspect 124:81–87; http://dx.doi.org/10.1289/ehp.1307909     

Changes in Mean Intake of Fatty Acids and Intake of Saturated and trans Fats from Potatoes: NHANES 2005–2006, 2007–2008, and 2009–2010

Studies have shown that higher than usual intakes of trans fatty acids (TFAs) have adverse effects on blood lipids. Because of this, in 2006 the US FDA mandated labeling of TFAs on food packages. The food and restaurant industries, including the potato industry, reformulated their foods to reduce or eliminate partially hydrogenated vegetable oils and TFAs. Before mandatory labeling, grain-based desserts, yeast breads, and French-fried potatoes (FFPs) were the top sources of TFAs in the food supply; by 2007, potato food manufacturers and quick-service restaurants had reduced or eliminated TFAs without increasing saturated fatty acids (SFAs). FFPs are no longer a source of TFAs in the food supply. This study examined energy and fatty acid intake among children aged 6–11 y, adolescents aged 12–18 y, and adults aged ≥19 y across 3 time periods by using data from the NHANES 2005–2006, 2007–2008, and 2009–2010. On average, intakes of total energy, total fat, SFAs, and monounsaturated fatty acids (MUFAs) decreased significantly between 2005–2006 and 2009–2010 among children and adolescents; however, the intake of polyunsaturated fatty acids (PUFAs) did not change. Among adults, intakes of total fat, SFAs, and MUFAs decreased; however, total energy and PUFA intake did not change. On the day of the 2009–2010 survey, ∼13% of children and 10% of adolescents reported consuming fried FFPs, whereas <7% of adults reported consumption of fried FFPs. Intakes of SFAs and TFAs from fried FFPs decreased significantly between 2005–2006 and 2009–2010 among children, adolescents, and adults. This study confirms that intake of TFAs from FFPs is trivial.     

Association of geomagnetic disturbances and suicides in Japan, 1999–2010

Objectives

Previous studies have shown a positive relationship between geomagnetic disturbances and an increased incidence of suicide. The Japanese suicide rate is the ninth highest in the world, but there have been no reports examining the relationship between geomagnetic disturbance and the number of suicides, and, therefore, this paper examines this relationship.

Methods

The number of Japanese suicides per month from January 1999 to December 2010 was obtained, and it was found that a total of 262,596 males and 102,539 females committed suicide during this period. To adjust the other factors which affect the number of suicides, a multiple linear regression analysis with backward elimination was carried out, with the monthly number of suicides as the response variable and the monthly mean K index value, monthly mean number of sunspots, monthly mean unemployment rate, proportion of elderly people (%), monthly mean air pressure (hPa), monthly mean air temperature (°C), monthly mean humidity (%), and monthly mean day length (h) as the explanatory variables.

Results

In the multiple linear regression analysis for males, the monthly mean K index value was associated with the monthly number of suicides, but in females, the monthly mean K index value was not associated with the monthly number of suicides.

Conclusion

In this study, we generated a hypothesis that geomagnetic disturbances may trigger male suicides.     

Urinary bisphenol-A,phthalate metabolites and body composition in US adults,NHANES 1999–2006

Background: Exposure to bisphenol-A (BPA) and phthalates is highly prevalent. Prior studies have not assessed associations between urinary levels of BPA and phthalate metabolites and body composition. Methods: National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2006 on adults aged ≥20 were analyzed by linear regression for associations between urinary BPA, monoethyl phthalate, monobutyl phthalate (MBP), monoethylhexyl phthalate (MEHP), and monobenzyl phthalate (MBzP) and lean mass, fat mass, and percent body fat. Results: BPA and phthalate metabolites were not independently associated with fat mass or percent body fat. Significant inverse associations were observed with lean mass, with the strongest association observed for BPA in men (mean lean mass 1.39 kg lower for quartile 4 vs. quartile 1, p trend = 0.02). Conclusions: BPA and some phthalates could have important, negative effects on muscle and may affect conditions related to deficits in lean mass, though additional research is needed.     

Association of Exposure to Phthalates with Endometriosis and Uterine Leiomyomata: Findings from NHANES, 1999–2004

Background

Phthalates are ubiquitous chemicals used in consumer products. Some phthalates are reproductive toxicants in experimental animals, but human data are limited.

Objective

We conducted a cross-sectional study of urinary phthalate metabolite concentrations in relation to self-reported history of endometriosis and uterine leiomyomata among 1,227 women 20–54 years of age from three cycles of the National Health and Nutrition Examination Survey (NHANES), 1999–2004.

Methods

We examined four phthalate metabolites: mono(2-ethylhexyl) phthalate (MEHP), monobutyl phthalate (MBP), monoethyl phthalate (MEP), and monobenzyl phthalate (MBzP). From the last two NHANES cycles, we also examined mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP). We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for potential confounders.

Results

Eighty-seven (7%) and 151 (12%) women reported diagnoses of endometriosis and leiomyomata, respectively. The ORs comparing the highest versus lowest three quartiles of urinary MBP were 1.36 (95% CI, 0.77–2.41) for endometriosis, 1.56 (95% CI, 0.93–2.61) for leiomyomata, and 1.71 (95% CI, 1.07–2.75) for both conditions combined. The corresponding ORs for MEHP were 0.44 (95% CI, 0.19–1.02) for endometriosis, 0.63 (95% CI, 0.35–1.12) for leiomyomata, and 0.59 (95% CI, 0.37–0.95) for both conditions combined. Findings for MEHHP and MEOHP agreed with findings for MEHP with respect to endometriosis only. We observed null associations for MEP and MBzP. Associations were similar when we excluded women diagnosed > 7 years before their NHANES evaluation.

Conclusion

The positive associations for MBP and inverse associations for MEHP in relation to endometriosis and leiomyomata warrant investigation in prospective studies.     

Association of Osteoarthritis with Perfluorooctanoate and Perfluorooctane Sulfonate in NHANES 2003–2008

Background: Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent, synthetic industrial chemicals. Perfluorinated compounds are linked to health impacts that may be relevant to osteoarthritis, cartilage repair, and inflammatory responses.Objectives: We investigated whether PFOA and PFOS exposures are associated with prevalence of osteoarthritis, and whether associations differ between men and women.Methods: We used multiple logistic regression to estimate associations between serum PFOA and PFOS concentrations and self-reported diagnosis of osteoarthritis in persons 20–84 years of age who participated in NHANES during 2003–2008. We adjusted for potential confounders including age, income, and race/ethnicity. Effects by sex were estimated using stratified models and interaction terms.Results: Those in the highest exposure quartile had higher odds of osteoarthritis compared with those in the lowest quartile [odds ratio (OR) for PFOA = 1.55; 95% CI: 0.99, 2.43; OR for PFOS = 1.77; 95% CI: 1.05, 2.96]. When stratifying by sex, we found positive associations for women, but not men. Women in the highest quartiles of PFOA and PFOS exposure had higher odds of osteoarthritis compared with those in the lowest quartiles (OR for PFOA = 1.98; 95% CI: 1.24, 3.19 and OR for PFOS = 1.73; 95% CI: 0.97, 3.10).Conclusions: Higher concentrations of serum PFOA were associated with osteoarthritis in women, but not men. PFOS was also associated with osteoarthritis in women only, though effect estimates for women were not significant. More research is needed to clarify potential differences in susceptibility between women and men with regard to possible effects of these and other endocrine-disrupting chemicals.     

Environmental lead and childhood blood lead levels in US children: NHANES, 1999–2006

Although blood lead levels in the United States have fallen dramatically since 1980, there remain subgroups of children with high blood lead levels. We assessed the relationship between environmental lead sources and blood lead levels in children ages 1 to 5 years from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Modeled ambient air lead levels and industrial lead releases at the census-tract level were assigned to each child's residence with adjustment for confounding factors. Of 3,223 children, 272 (8.4%) had blood lead levels ≥ 5 ug/dL. Industrial releases (2,252 vs 1,696 lbs/mi²) and ambient air lead levels (2.28 vs 1.75 ng/m³) were greater in exposed versus unexposed children. For every 10,000 lb/mi² increase in inverse distance squared weighted exposure, there was a 1.13% increase (95% CI: 0.45%, 1.81%) in blood lead (p = .001).