Relationship of bone and blood lead levels to psychiatric symptoms: the normative aging study

Blood and bone lead levels were used to investigate lead's potential effect on psychiatric symptoms among middle-aged to elderly men from the Normative Aging Study. Symptoms were assessed using the Brief Symptom Inventory (BSI) and analyzed as individual outcomes as well as a measure that combined anxiety, depression, and phobic anxiety. Blood and bone lead averaged 6.3 microg/dL (standard deviation [SD] = 4.16), 21.9 microg/g (SD = 13.5), and 32.1 microg/g (SD = 19.8) for blood, tibia, and patella lead, respectively. In logistic regression models that adjusted for age, alcohol intake, employment status, and education status, we found that patella bone lead was significantly associated with an increased risk of phobic anxiety and the combined outcome measure at the P 相似文献   

Dietary calcium as a potential modifier of the relationship of lead burden to blood pressure

BACKGROUND: Cumulative lead burden and low dietary calcium have been independently associated with increased risk of hypertension. There is evidence of an interaction between these factors. We tested the hypothesis that dietary calcium intake modifies the relationship between lead burden and hypertension. METHODS: A total of 471 men from the Normative Aging Study were evaluated. Bone lead was assessed using a K-x-ray fluorescence instrument, and information on dietary calcium intake was obtained with a self-administered semiquantitative food frequency questionnaire. RESULTS: We categorized 259 subjects (55%) as having low calcium intake (< or =800 mg/d) and 212 subjects (45%) as having higher calcium intake. In logistic regression models stratified by dietary calcium intake, tibia lead had a weak association with hypertension among subjects with low dietary calcium (odds ratio for 1-standard deviation increase in tibia lead = 1.30; 95% confidence interval = 0.97-1.74) but not in subjects with higher dietary calcium intake. Similarly, blood lead was associated with hypertension only in subjects with low calcium intake. We also found evidence of an interaction between dietary calcium intake and body mass index. CONCLUSIONS: High bone and blood lead increased the likelihood of hypertension, particularly among subjects with low dietary calcium intake. Dietary calcium may be helpful in prevention of hypertension induced by elevated lead burden.     

Cumulative community-level lead exposure and pulse pressure: the normative aging study

BACKGROUND: Pulse pressure increases with age in industrialized societies as a manifestation of arterial stiffening. Lead accumulates in the vasculature and is associated with vascular oxidative stress, which can promote functional and structural vascular disease. OBJECTIVES: We tested the hypothesis that cumulative community-level lead exposure, measured with K-X-ray fluorescence, is associated with pulse pressure in a cohort of adult men. METHODS AND RESULTS: In a cross-sectional analysis of 593 men not treated with antihypertensive medication, tibia lead was positively associated with pulse pressure (p < 0.001). Adjusting for age, race, diabetes, family history of hypertension, education, waist circumference, alcohol intake, smoking history, height, heart rate, fasting glucose, and total cholesterol-to-HDL ratio, increasing quintiles of tibia lead remained associated with increased pulse pressure (ptrend = 0.02). Men with tibia lead above the median (19.0 microg/g) had, on average, a 4.2-mmHg (95% confidence interval, 1.9-6.5) higher pulse pressure than men with tibia lead level below the median. In contrast, blood lead level was not associated with pulse pressure. CONCLUSIONS: These data indicate that lead exposure may contribute to the observed increase in pulse pressure that occurs with aging in industrialized societies. Lead accumulation may contribute to arterial aging, perhaps providing mechanistic insight into the observed association of low-level lead exposure with cardiovascular mortality.     

Association of serum albumin with blood pressure in the normative aging study.

Little is known regarding serum albumin's epidemiologic relation to chronic disease. The relation of serum albumin to blood pressure was assessed in a longitudinal study of men who have been seen at 3- to 5-year intervals since the early 1960s. The authors analyzed data from over 20 years of observation using cross-sectional multiple regression models of blood pressure that allow for the correlation between repeated measures on the same individual (GLMIC models), longitudinal GLMIC models that incorporate terms for the interaction of time with serum albumin at baseline, and models of the slope of individuals' blood pressure over time. Serum albumin levels were found to have a consistently strong relation with both systolic blood pressure and diastolic blood pressure in the cross-sectional GLMIC models only. This relation did not change appreciably when covariates for age, body mass index, alcohol ingestion, smoking, serum calcium, hematocrit, heart rate, and antihypertensive medications were added. A rise in serum albumin of 1 g/dl was associated with 1.79-mmHg and 0.91-mmHg increases in systolic blood pressure and diastolic blood pressure, respectively. This phenomenon may be related to experimental studies linking tryptophan, the only amino acid to bind noncovalently to serum albumin, to a blood pressure-lowering effect mediated by promotion of 5-hydroxytryptamine synthesis in the brain.     

Associations of toenail arsenic, cadmium, mercury, manganese, and lead with blood pressure in the normative aging study

Background: Arsenic, cadmium, mercury, and lead are associated with cardiovascular disease in epidemiologic research. These associations may be mediated by direct effects of the metals on blood pressure (BP) elevation. Manganese is associated with cardiovascular dysfunction and hypotension in occupational cohorts.Objectives: We hypothesized that chronic arsenic, cadmium, mercury, and lead exposures elevate BP and that manganese lowers BP.Methods: We conducted a cross-sectional analysis of associations between toenail metals and BP among older men from the Normative Aging Study (n = 639), using linear regression and adjusting for potential confounders.Results: An interquartile range increase in toenail arsenic was associated with higher systolic BP [0.93 mmHg; 95% confidence interval (CI): 0.25, 1.62] and pulse pressure (0.76 mmHg; 95% CI: 0.22, 1.30). Positive associations between arsenic and BP and negative associations between manganese and BP were strengthened in models adjusted for other toenail metals.Conclusions: Our findings suggest associations between BP and arsenic and manganese. This may be of public health importance because of prevalence of both metal exposure and cardiovascular disease. Results should be interpreted cautiously given potential limitations of toenails as biomarkers of metal exposure.     

Bone lead levels and blood pressure endpoints: a meta-analysis

BACKGROUND: Previous reviews have shown increases in blood pressure and hypertension associated with increases in lead levels in blood. We performed a meta-analysis of the association of bone lead levels with systolic blood pressure, diastolic blood pressure, and hypertension using published data. METHODS: We searched Medline, Embase, and Toxline for epidemiologic studies on bone lead levels and blood pressure endpoints. We used inverse-variance weighted random-effects models to summarize the association of tibia or patella lead levels with blood pressure endpoints. RESULTS: We summarized data from 3 prospective studies and 5 cross-sectional studies. All studies measured lead levels in tibia bone and 3 studies measured lead levels in patella. For a 10 microg/g increase in tibia lead, the cross-sectional summary increases in blood pressure were 0.26 mm Hg for systolic (95% confidence interval = 0.02 to 0.50) and 0.02 mm Hg for diastolic (-0.15 to 0.19). The summary odds ratio for hypertension was 1.04 (1.01 to 1.07). For a 10 microg/g increase in patella lead, the summary odds ratio for hypertension was 1.04 (0.96 to 1.12). CONCLUSION: Systolic blood pressure and hypertension risk were associated with lead levels in tibia bone, but the magnitude of the summary estimates was small. These summary estimates, however, were based on published data and we could not evaluate nonlinear dose-response relationships, the relative contribution of bone and blood lead levels, or the influence of differences in study populations. A more detailed characterization of the association of bone lead levels and blood pressure endpoints would require a pooled analysis of individual participant data from existing studies.     

Work hygienic behaviour as modifier of the lead air-lead blood relation

Summary Knowledge of hygienic behaviour at the workplace appears to explain the low correlation between external and internal exposure. Differences in hygienic behaviour explain at least the same magnitude of variation in levels of lead in blood as the level of lead in air. Adding hygienic behaviour to the lead air-lead blood model increases the accuracy of prediction of PbB. In this study, the frequency of putting on/off gloves and the frequency of hand-mouth nose/shunt are the strongest modifiers of the PbA-PbB relation. In general, the actual behaviour of workers exposed to chemical agents may explain the often observed poor or moderate relationships between environmental and biological monitoring parameters of chemical exposure in occupational health studies.     

Association between hemochromatosis genotype and lead exposure among elderly men: the normative aging study

Because body iron burden is inversely associated with lead absorption, genes associated with hemochromatosis may modify body lead burden. Our objective was to determine whether the C282Y and/or H63D hemochromatosis gene (HFE) is associated with body lead burden. Patella and tibia lead levels were measured by K X-ray fluorescence in subjects from the Normative Aging Study. DNA samples were genotyped for C282Y and H63D using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). A series of multivariate linear regression models were constructed with bone or blood lead as dependent variables; age, smoking, and education as independent variables; and C282Y or H63D as independent risk factors and/or effect modifiers. Of 730 subjects, 94 (13%) carried the C282Y variant and 183 (25%) carried the H63D variant. In the crude analysis, mean tibia, patella, and blood lead levels were consistently lower in carriers of either HFE variant compared with levels in subjects with wild-type genotypes. In multivariate analyses that adjusted for age, smoking, and education, having an HFE variant allele was an independent predictor of significantly lower patella lead levels (p < 0.05). These data suggest that HFE variants have altered kinetics of lead accumulation after exposure. Among elderly men, subjects with HFE variants had lower patella lead levels. These effects may be mediated by alterations in lead toxicokinetics via iron metabolic pathways regulated by the HFE gene product and body iron stores.     

The independent contribution of bone and erythrocyte lead to urinary lead among middle-aged and elderly men: the normative aging study

Plasma is the component of blood from which lead is free to cross cell membranes and cause organ toxicity. Plasma lead levels, however, are extremely low and difficult to measure. Urinary lead originates from plasma lead that has been filtered at the glomerular level; thus, urinary lead adjusted for glomerular filtration rate serves as a proxy for plasma lead levels. In this investigation we examined the interrelationships of lead levels in whole blood corrected by hematocrit [i.e., erythrocyte lead (EPb)], trabecular bone (TBoPb), cortical bone (CBoPb), and urine excreted over 24 hr (UPb); all samples were obtained from 71 middle-aged and elderly men with no known occupational lead exposures. Lead was measured by graphite furnace atomic absorption spectroscopy (blood), K-X-ray fluorescence (bone), and inductively coupled plasma mass spectroscopy (urine). Lead levels were generally low, with mean EPb, TBoPb, and CBoPb values of 13.8, 31.1, and 21.7 microg/g, respectively, and a median UPb value of 6.15 microg/day. In generalized additive models adjusted for body weight and creatinine clearance rate, both EPb and bone lead variables remained independently and significantly associated with UPb. This finding suggests that bone influences plasma lead in a manner that is independent of the influence of erythrocytic lead on plasma lead. Thus, the superiority of bone lead over blood lead in predicting some chronic forms of toxicity may be mediated through bone's influence on plasma lead. In addition, this study suggests that measurement of urinary lead might be useful as a proxy for plasma lead levels in studies of lead toxicity.     

Body fat distribution, blood pressure, and hypertension. A prospective cohort study of men in the normative aging study.

The relation between the abdominal accumulation of body fat, blood pressure, and hypertension was assessed prospectively among 1972 male participants in the Veterans Administration Normative Aging Study. Body mass index (BMI = weight [kg]/height [m]2) and the ratio of abdominal circumference to hip breadth (AC/HB), measured at regular exams, were used as indices of total adiposity and body fat distribution, respectively. Considering blood pressure as a continuous outcome variable (in models that allowed for intraclass correlation), the AC/HB ratio was significantly positively associated with both diastolic and systolic blood pressure (P < 0.001), adjusting for age and BMI. Blood pressure was dichotomized and hypertension risk was assessed using the proportional hazards model, adjusting for age and BMI. Seven hundred cases of hypertension were recorded by study physicians during 35,496 person-years of follow-up. The risk of hypertension increased approximately three-fold (95% confidence interval, 1.7 to 5.2) with a change of one unit in the AC/HB ratio. These estimates were little changed when the effects of smoking and alcohol intake were considered. Thus, the abdominal accumulation of body fat, apart from overall level of adiposity, was associated with both increased blood pressure and an increased risk of hypertension.     

Condition and type of housing as an indicator of potential environmental lead exposure and pediatric blood lead levels

Environmental evaluations in a prospective behavioral study of children with blood lead levels up to about 50 micrograms/dl were performed by an intensive environmental survey and by exterior visual evaluation of housing quality. Serial blood lead values for infants in the study were compared to exterior housing type and quality, which itself was also compared with results of the intensive environmental evaluation. Five housing condition and type categories were defined: public housing; private housing (satisfactory, deteriorated, and dilapidated); and rehabilitated private housing. In this interim report on the first subset of available data, the housing categories were found to differ in paint and environment dust lead levels, with public and rehabilitated housing having lowest values. Blood lead concentrations of children differed across housing categories as early as 6 months of age, with children residing in public housing having lowest levels, followed by those in rehabilitated housing. The spread in mean blood lead concentrations among the housing quality categories increased with increasing age of the children. Housing category accounted for over one-half of the blood lead variability in 18-month-old children.     

胶体钯化学改进剂石墨炉原子吸收光谱法测定血中铅

目的 建立胶体钯化学改进剂用于石墨炉原子吸收光谱法测定血中铅的方法。方法 血样经5%(V/V)硝酸沉淀蛋白质后,以胶体钯作为化学改进剂,石墨炉原子吸收光谱法直接测定。结果 方法的相关系数大于0.999,检出限为0.6μg/L,样品加标的回收率为96.0%～100.7%,相对标准偏差<2%。对标准物质进行分析,测定结果在证书值范围内。结论 该方法准确、灵敏、简便,可以满足血中铅的测定     

Occupational exposure to lead and blood pressure: a study in 105 workers

A group of workers, occupationally exposed to lead and cadmium compounds (n = 53), was compared to a group of workers not exposed to these metals (n = 52). The average values of systolic, diastolic, and mean blood pressure were found to be higher in the exposed group (p less than 0.05). In contrast with the correlation between CdU and blood pressure, the correlation between PbB and systolic and mean blood pressure remained statistically significant after controlling for age and pulse rate (r = 0.22, p less than 0.05). The prevalence of potential hypertension (defined as systolic blood pressure greater than or equal to 160 mm Hg and/or diastolic blood pressure greater than or equal to 95 mm Hg and/or under treatment for hypertension) was higher in the exposed group, but the observed relative risk was not statistically significant: relative risk = 1.91 (95% confidence limits, 0.90-4.05). Furthermore, a significant correlation between PbB and Hgb (r = -0.28, p = 0.004) was observed. Differences in kidney function, as assessed in this study, were not detected.     

Relationship of blood lead levels to blood pressure in exhaust battery storage workers

Several researches has focused the hypothesis that low blood lead levels could be associated with an increased risk of hypertension. To assess the relation between occupational lead exposure and elevated blood pressure a group of 27 workers, age range from 27 to 62 years, mean (SD) 36.52 (+/- 8.16) yr; length of employment mean (DS) 2.97 (+/- 1.67) yr, were recruited as study subjects. The following variables were measured: blood lead concentration (BPb), delta-Aminolevulinic Acid Dehydratase (ALAD) activity, Zinc Protoporphirin (ZPP), creatinine, hematocrit, Body Mass Index (BMI) and Systolic Blood Pressure (SBP) and Diastolic Blood (DBP) Pressure. The results showed that long term occupational exposure was related to a slight increase of systolic and diastolic blood pressure among workers who had been exposed to higher level of lead with respect to workers exposed to lower level of lead. Furthermore, blood lead concentration (BPb) and ZPP resulted higher among workers exposed to higher level of ambient lead, while in the same group of workers ALAD activity resulted more inhibited. The authors concluded long term cumulative lead exposure can significantly increase blood pressure in low level Pb exposed workers.     

Bone lead and blood lead levels in relation to baseline blood pressure and the prospective development of hypertension: the Normative Aging Study

Between 1991 and 1997, the authors studied 833 participants of the Normative Aging Study in a substudy of bone lead levels (measured by K-shell x-ray fluorescence), blood lead levels, and hypertension. Among these subjects, 337 were classified as normotensive, and 182 and 314 were classified as having borderline and definite hypertension, respectively, at baseline. These bone and blood lead levels were typical of those of community-exposed men. Among the 519 subjects with no history of definite hypertension at baseline, cross-sectional analyses revealed positive associations between systolic blood pressure and bone lead levels. Of the 474 subjects who were free from definite hypertension at baseline and had follow-up data, 74 new cases of definite hypertension were reported. Baseline bone lead levels were positively associated with incidence of hypertension. In proportional hazards models that controlled for age, age squared, body mass index, and family history of hypertension, an increase in patella (trabecular) lead from the midpoint of the lowest quintile to that of the highest quintile was associated with a rate ratio of definite hypertension of 1.71 (95% confidence interval: 1.08, 2.70). No association was found with blood lead level. These results support the hypothesis that cumulative exposure to lead, even at low levels sustained by the general population, may increase the risk of hypertension.     

A study of pediatric blood lead levels in a lead mining area in South Africa

This study aimed to determine the blood lead distributions among young children in the lead mining town of Aggeneys in South Africa's Northern Cape Province, and in the comparison community of Pella, about 40 Km away. A further objective of the study was to explore factors associated with elevated blood lead levels. Children aged between 6 and 10 years (average age, 8 years) were studied, 86 from Aggeneys and 68 from Pella. The results showed that blood lead levels among the children of Aggeneys averaged around 16 microg/dL, while in Pella the mean blood lead level equaled 13 microg/dL. Overall, children with raised blood lead levels performed less well at school relative to other children. Within Aggeneys, fathers of "high" lead children tended to shower at work rather than at home, which may have been insufficient to prevent lead from being transported into the home. In conclusion, more stringent environmental control measures are needed, as well as stricter personal hygiene measures, to prevent childhood lead exposure in the mining community.     

婴幼儿血铅水平及其影响因素

目的　了解婴幼儿的血铅水平及其影响因素。　方法　用石墨炉原子吸收光谱法测定2 6 2例婴幼儿末梢血铅浓度 ,并进行铅中毒影响因素的调查。　结果　婴幼儿血铅算术平均值为0 .4 3μmol/L,范围为 0 .10～ 1.4 5 μmol/L,铅中毒发生率为 37.0 2 % (97/2 6 2 )。不同性别、不同年龄婴幼儿血铅水平及铅中毒发生率差异无显著性 (P>0 .0 5 ) ,各年龄婴幼儿血铅等级分布以 I级最高 ,婴幼儿铅中毒属 II～ III级。饭前不洗手、经常在马路边玩耍、经常看彩色书刊后不洗手、父母职业、住房为 1990年以后建造的是影响婴幼儿血铅水平的因素。　结论　婴幼儿已受到不同程度的铅损伤 ,应引起家长及有关方面的重视     

Prediction of children's blood lead levels on the basis of household-specific soil lead levels

To help guide policy decisions about removing lead-contaminated soils, the authors estimated a regression model for predicting a child's blood lead level on the basis of his or her household-specific soil lead level. The data analyzed were blood lead levels (1-45 micrograms/dl) and household-specific soil lead levels (53-20,700 ppm) of 596 children aged 1-5 years who lived in the Helena Valley of Montana and the Silver Valley of Idaho during August 1983. A non-threshold, multiple linear regression model indicated that the estimated mean natural log transformed blood lead level increased by 0.231 micrograms/dl for each unit increase in natural log transformed soil lead level (ppm), after adjusting for the average number of daily outdoor play hours and whether someone in the household smoked. The model predicted that, at a soil lead level of 1,000 ppm, a child who does not play outside and who does not live in a household where someone smokes would be at low risk of lead toxicity (blood lead level between 4 and 24 micrograms/dl).     

Effects of air pollution on heart rate variability: the VA normative aging study

Reduced heart rate variability (HRV), a marker of poor cardiac autonomic function, has been associated with air pollution, especially fine particulate matter [< 2.5 microm in aerodynamic diameter (PM2.5)]. We examined the relationship between HRV [standard deviation of normal-to-normal intervals (SDNN), power in high frequency (HF) and low frequency (LF), and LF:HF ratio] and ambient air pollutants in 497 men from the Normative Aging Study in greater Boston, Massachusetts, seen between November 2000 and October 2003. We examined 4-hr, 24-hr, and 48-hr moving averages of air pollution (PM2.5, particle number concentration, black carbon, ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide). Controlling for potential confounders, HF decreased 20.8% [95% confidence interval (CI), 4.6-34.2%] and LF:HF ratio increased 18.6% (95% CI, 4.1-35.2%) per SD (8 microg/m3) increase in 48-hr PM2.5. LF was reduced by 11.5% (95% CI, 0.4-21.3%) per SD (13 ppb) increment in 4-hr O3. The associations between HRV and PM2.5 and O3 were stronger in people with ischemic heart disease (IHD) and hypertension. The associations observed between SDNN and LF and PM2.5 were stronger in people with diabetes. People using calcium-channel blockers and beta-blockers had lower associations between O3 and PM2.5 with LF. No effect modification by other cardiac medications was found. Exposures to PM2.5 and O3 are associated with decreased HRV, and history of IHD, hypertension, and diabetes may confer susceptibility to autonomic dysfunction by air pollution.