Bone Lead Concentrations Research Articles

Determining How Gavaging Laying Hens with Lead (Pb) Affects Lead Concentration in Table Eggs, Bone, blood, and Liver

Previous research has demonstrated that lead (Pb2+, for the remainder of the paper referred to as Pb) and other heavy metals are present in table eggs from backyard birds. While the source of Pb exposure is unknown, exposure to the environment via the foraging behavior of backyard poultry is likely a significant factor. A longitudinal cohort study was conducted to better understand how oral Pb consumption correlates with Pb concentration in table eggs and other physiological compartments (i.e. bone, blood, and liver). In order of absolute mean concentration, Pb was most present in bone (226.24 ppb experimental vs. 31.00 ppb control), blood (14.47 ppb experimental vs 0.27 ppb control), liver (11.24 ppb experimental vs 0.75 ppb control), and egg (1.17 ppb experimental vs 0.06 ppb control). The low concentration of Pb in table eggs implies that Pb preferentially accumulates in other tissues aside from the egg. While this study showed that eggs have the lowest overall tropism for Pb, the presence of Pb in other tissues demonstrates a public health risk when chickens are orally exposed to Pb via oral consumption.

Lead exposure of mainland Australia's top avian predator

Lead (Pb) toxicity, through ingestion of lead ammunition in carcasses, is a threat to scavenging birds worldwide, but has received little attention in Australia. We analyzed lead exposure in the wedge-tailed eagle (Aquila audax), the largest raptor species found in mainland Australia and a facultative scavenger. Eagle carcasses were collected opportunistically throughout south-eastern mainland Australia between 1996 and 2022. Lead concentrations were measured in bone samples from 62 animals via portable X-ray fluorescence (XRF). Lead was detected (concentration >1 ppm) in 84% (n = 52) of the bone samples. The mean lead concentration of birds in which lead was detected was 9.10 ppm (±SE 1.66). Bone lead concentrations were elevated (10–20 ppm) in 12.9% of samples, and severe (>20 ppm) in 4.8% of samples. These proportions are moderately higher than equivalent data for the same species from the island of Tasmania, and are comparable to data from threatened eagle species from other continents. Lead exposure at these levels is likely to have negative impacts on wedge-tailed eagles at the level of the individual and perhaps at a population level. Our results suggest that studies of lead exposure in other Australian avian scavenger species are warranted.

Expanding the use of portable XRF to monitor lead exposure in an Australian duck species two decades after a ban on lead shot

There is growing worldwide recognition of the threat posed by toxic lead for wildlife and humans. Lead toxicity from ammunition has been shown to be a threat to waterbirds across the globe. Lead shot was banned for all waterfowl hunting in Victoria, Australia, in 2002. However, no assessments of lead exposure in Australian waterfowl have been published since the 1990s. Our aim was to estimate contemporary lead exposure via measuring bone lead concentrations in a harvested dabbling duck, the Pacific black duck (Anas superciliosa). We collected wings from 77 Pacific black ducks, spanning 2018 (n = 30) and 2021 (n = 47), from nine sites with long-term histories of regular waterfowl hunting. We sought to validate portable X-ray fluorescence (XRF) for this purpose by taking a piece of humerus bone from each bird, and measuring lead concentration (mg/kg), first via non-destructive XRF and then via destructive inductively coupled plasma mass spectrometry (ICP-MS) and validated the relationship via regression analysis. Portable XRF bone lead measurement demonstrated a strong correlation with ICP-MS results using root-transformed regression (R2 = 0.85). Greater than 92 % of ducks had only background lead exposure (<10 mg/kg). When compared to historical studies in the same species at similar field sites from the 1990s, lead exposure levels were considerably lower, with mean lead concentrations ∼2-fold lower (3.7 c.f. 7.7 mg/kg), and the frequency of birds with severe lead exposure (>20 mg/kg) ∼3-fold lower (2.6 c.f. 7.5 %). Our results confirm that portable XRF is a useful option for measurement of bone lead in Australasian waterbird species. Our findings also demonstrate that a ban on the use of lead shot around 20 years ago has been associated with a substantial reduction in lead exposure in at least one species of waterfowl.

Predicting cumulative lead (Pb) exposure using the Super Learner algorithm

Chronic lead (Pb) exposure causes long term health effects. While recent exposure can be assessed by measuring blood lead (half-life 30 days), chronic exposures can be assessed by measuring lead in bone (half-life of many years to decades). Bone lead measurements, in turn, have been measured non-invasively in large population-based studies using x-ray fluorescence techniques, but the method remains limited due to technical availability, expense, and the need for licensing radioactive materials used by the instruments. Thus, we developed prediction models for bone lead concentrations using a flexible machine learning approach--Super Learner, which combines the predictions from a set of machine learning algorithms for better prediction performance. The study population included 695 men in the Normative Aging Study, aged 48 years and older, whose bone (patella and tibia) lead concentrations were directly measured using K-shell-X-ray fluorescence. Ten predictors (blood lead, age, education, job type, weight, height, body mass index, waist circumference, cumulative cigarette smoking (pack-year), and smoking status) were selected for patella lead and 11 (the same 10 predictors plus serum phosphorus) for tibia lead using the Boruta algorithm. We implemented Super Learner to predict bone lead concentrations by calculating a weighted combination of predictions from 8 algorithms. In the nested cross-validation, the correlation coefficients between measured and predicted bone lead concentrations were 0.58 for patella lead and 0.52 for tibia lead, which has improved the correlations obtained in previously-published linear regression-based prediction models. We evaluated the applicability of these prediction models to the National Health and Nutrition Examination Survey for the associations between predicted bone lead concentrations and blood pressure, and positive associations were observed. These bone lead prediction models provide reasonable accuracy and can be used to evaluate health effects of cumulative lead exposure in studies where bone lead is not measured.

Association between Bone Lead Concentration and Aggression in Youth from a Sub-Cohort of the Birth to Twenty Cohort.

Background: An association between blood-lead levels and aggression has been demonstrated in children and adolescent youth in South Africa. However, there are limited studies that have assessed aggression as an outcome for cumulative lead exposure using bone lead concentration. This study aims to assess the association between bone lead concentration and aggressive behaviour among a sample of youth in South Africa. Methods: Bone lead in 100 participants (53 males and 47 females) recruited and followed in the Birth to Twenty (BT20) Cohort were measured using 109 Cd-based, K-shell X-ray fluorescence (KXRF). The Buss–Perry Aggression questionnaire was used to measure aggressive behaviour. Linear regression models were fitted to determine the association between aggression score for physical, verbal, anger and hostility and bone lead, adjusting for known confounders. Results: A one-microgram-per-gram increase in bone lead was found to increase the score for all four scales of aggression, but significantly only for anger (β = 0.2 [95% CI 0.04–0.370]). Psychosocial factors such as a history of family violence and exposure to neighbourhood crime were significant predictors for aggression. Conclusions: The study provides a preliminary overview of the relationship between cumulative lead exposure and behavioural problems such as aggression. A larger sample, across exposed communities, may prove more definitive in further investigating the association between these two important public health factors and to maximize generalizability.

A novel calibration for L-shell x-ray fluorescence measurements of bone lead concentration using the strontium Kβ/Kα ratio

Objective. Lead (Pb) is a well-known toxic element. In vivo bone Pb concentration measurement is a long-term exposure metric complementary to blood Pb concentration measurement which is a metric of recent exposure. In vivo human tibia bone Pb measurements using Pb K-shell or L-shell x-ray fluorescence (KXRF or LXRF) emissions were developed in the 1980s. KXRF bone Pb measurements using Cd-109 gamma rays and coherent-to-fluorescence ratio to account for differences between phantom and in vivo measurements, was employed in human studies. Bone Pb LXRF method employed x-ray tubes. However, calibration procedures using ultrasound measurements of the soft tissue thickness (STT) proved inaccurate. Approach. In this study, bone and soft tissue (ST) phantoms simulated in vivo bone Pb measurements. Seven plaster-of-Paris cylindrical bone phantoms containing 1.01 mg g−1 of strontium (Sr) were doped with Pb in 0, 8, 16, 29, 44, 59, and 74 μg g−1 concentrations. Polyoxymethylene (POM), resin, and wax were each used to fabricate four ST phantoms in the approximate 1–4 mm thickness range. Pb LXRF measurements were performed using a previously developed optimal grazing incidence position method. Main results. Linear attenuation coefficients measurements of ST materials indicated that POM and resin mimicked well attenuation of Pb x-rays in skin and adipose tissue, respectively. POM and resin data indicated a bone Pb detection limit of 20 μg g−1 for a 2 mm STT. Derived relationships between the Pb concentration, Pb LXRF and Sr K β /K α ratio data did not require STT knowledge. Applied to POM and resin data, the new calibration method yielded unbiased results. Significance. In vivo bone Pb measurements in children were suggested following considerations of radiation dose, STT, detectability and distribution of Pb and Sr in bone. This research meets with the concerns regarding the negative effects of low levels of Pb exposure on neurodevelopment of children.

Evaluation and updates to the Leggett model for pharmacokinetic modeling of exposure to lead in the workplace – Part I adjustments to the adult systemic model

California’s Division of Occupational Safety and Health has initiated a process to update its standards for exposure to lead in workplaces. In support of this effort, the state’s Office of Environmental Health Hazard Assessment evaluated the age-specific, bio-kinetic model of lead metabolism in humans, originally published by R.W. Leggett in 1993. This model was ultimately chosen for its physiologic realism and practicality in characterizing the relationship between air lead concentrations and blood lead levels in chronically exposed worker and its practicality in making necessary adjustments. Leggett’s original model systematically under-predicts bone and blood levels in workers such that several adjustments to the parameters are needed to improve predictions for occupational exposure scenarios. The aim of this work is to incorporate new information about the bio-kinetics of lead in workers and to adjust the Leggett model to improve its predictions.The Leggett model was evaluated by comparing its predictions with information on lead concentrations in bone, blood, and urine from workers and other chronically exposed adults. Key model parameters were identified based upon a review of the relevant exposure assessment and modeling literature. Adjustments to the model parameters were made based on empirical evidence. They included reducing the level of lead in blood (BLL) where the rate of decrease in red blood cell binding begins and ends, lead accumulation rate in cortical bone, the rate of lead elimination in trabecular bone, and rate of lead transferred from diffusible plasma to urine. Regression methods and visual inspection of plotted data were used to assess the effect of adjustments on model predictions. When compared with the original, the adjusted Leggett model more accurately predicted lead concentrations observed in active and retired workers. Also, the adjusted Leggett model required less lead uptake to reach the same BLLs for BLLs less than 25 µg/dL and more time for BLLs to decline than the original Leggett model. These findings are important for defining an adequately protective occupational standard for lead exposure.

Estimating the causal effect of prenatal lead exposure on prepulse inhibition deficits in children and adolescents

During pregnancy, maternal lead from earlier exposures mobilizes and crosses placental barriers, placing the developing fetus at risk for lead exposure and neurodevelopmental deficits. Some neuronal circuits known to be affected in neurodevelopment disorders can be probed with simple physiological behavioral paradigms. One such neural biomarker is Pre-Pulse Inhibition (PPI), an indicator of adequate sensorimotor gating processing. In clinical studies, deficits in PPI have been associated with neurodevelopmental disorders in human subjects. To our knowledge, no studies have examined the use of PPI as a biomarker of toxicant effects on the brain in epidemiological studies. We aimed to estimate the causal effect of prenatal lead exposure, assessed by maternal cortical bone lead concentrations, on PPI in 279 children from Mexico City. in vivo maternal cortical bone lead measurements were taken at four weeks postpartum at the mid-tibia shaft using a K-Shell X-ray fluorescence instrument. PPI recording occurred in an isolated clinical setting and eye blink responses were measured using electromyography. We assessed if the conditions for causal inference held in our study and used the results of our assessment to estimate the causal effect of prenatal lead exposure on PPI using an ordinary least squares regression model, a marginal structural model, and the parametric g-formula. Results were consistent across the three modeling approaches. For the parametric g-formula, a one standard deviation (10.0 μg/g) increase in prenatal lead significantly reduced PPI by approximately 19.0 % (95 % CI: 5.4 %, 34.3 %). This decrease is similar in magnitude to clinical studies on schizophrenia, which have observed PPI impairments in patients with schizophrenia as compared to controls. Our results are consistent with findings from other studies establishing an association between lead exposure and neurodevelopmental disorders in children and suggest that PPI may be useful as an objective biomarker of toxicant effects on the brain.

Effect of Dietary Sodium and Potassium Intake on the Mobilization of Bone Lead among Middle-Aged and Older Men: The Veterans Affairs Normative Aging Study

Bone is a major storage site as well as an endogenous source of lead in the human body. Dietary sodium and potassium intake may play a role in the mobilization of lead from bone to the circulation. We examined whether association between bone lead and urinary lead, a marker of mobilized lead in plasma, was modified by dietary intake of sodium and potassium among 318 men, aged 48–93 years, in the Veterans Affairs (VA) Normative Aging Study. Dietary sodium and potassium were assessed by flame photometry using 24-h urine samples, and a sodium-to-potassium ratio was calculated from the resulting measures. Patella and tibia bone lead concentrations were measured by K-shell-x-ray fluorescence. Urinary lead was measured by inductively coupled plasma mass spectroscopy in 24-h urine samples. Linear regression models were used to regress creatinine clearance-corrected urinary lead on bone lead, testing multiplicative interactions with tertiles of sodium, potassium, and sodium-to-potassium ratio, separately. After adjustment for age, body mass index, smoking, vitamin C intake, calcium, and total energy intake, participants in the highest tertile of sodium-to-potassium ratio showed 28.1% (95% CI: 12.5%, 45.9%) greater urinary lead per doubling increase in patella lead, whereas those in the second and lowest tertiles had 13.8% (95% CI: −1.7%, 31.7%) and 5.5% (95% CI: −8.0%, 21.0%) greater urinary lead, respectively (p-for-interaction = 0.04). No statistically significant effect modification by either sodium or potassium intake alone was observed. These findings suggest that relatively high intake of sodium relative to potassium may play an important role in the mobilization of lead from bone into the circulation.

Effect of Dietary Sodium and Potassium Intake on the Mobilization of Bone Lead among Middle-aged and Older Men

Bone is a major storage site as well as an endogenous source of lead in the human body. Dietary sodium and potassium intake may play a role in the mobilization of lead from bone to the circulation. We examined whether association between bone lead and urinary lead, a marker of mobilized lead in plasma, was modified by dietary intake of sodium and potassium among 318 men, aged 48-93 years, in the Veterans Affairs (VA) Normative Aging Study. Dietary sodium and potassium were assessed by flame photometry using 24-h urine samples, and a sodium-to-potassium ratio was calculated from the resulting measures. Patella and tibia bone lead concentrations were measured by K-shell-x-ray fluorescence. Urinary lead was measured by inductively coupled plasma mass spectroscopy in 24-h urine samples. Linear regression models were used to regress creatinine clearance-corrected urinary lead on bone lead, testing multiplicative interactions with tertiles of sodium, potassium, and sodium-to-potassium ratio, separately. After adjustment for age, body mass index, smoking, vitamin C intake, calcium, and total energy intake, participants in the highest tertile of sodium-to-potassium ratio showed 28.1% (95% CI: 12.5%, 45.9%) greater urinary lead per doubling increase in patella lead, whereas those in the second and lowest tertiles had 13.8% (95% CI: -1.7%, 31.7%) and 5.5% (95% CI: -8.0%, 21.0%) greater urinary lead, respectively (p-for-interaction = 0.04). No statistically significant effect modification by either sodium or potassium intake alone was observed. These findings suggest that relatively high intake of sodium relative to potassium may play an important role in the mobilization of lead from bone into the circulation.

Alpine accentors as monitors of atmospheric long-range lead and mercury pollution in alpine environments.

Mercury and lead are deposited in the West Carpathians as long-range transported air pollution. The Alpine accentor (Prunella collaris) was recognized as a cost-effective biomonitor, and used to investigate the bioavailability of contaminants in large alpine areas. The outer tail feathers and blood of the alpine accentors were used for assessment of atmospheric mercury and lead contamination, respectively. Mean mercury levels in feathers of accentors averaged at 1.15μg/g (SE = 0.105, n = 40). There were no temporal variations in mercury concentrations. Mean blood lead levels were at 5.2μg/dL (SE = 0.5, n= 27), showing a slight decreasing trend from July to October. Juveniles were not more susceptible to lead accumulation than adults. Bone lead concentrations that increase with age reflect a bioaccumulation effect. A statistically significant negative correlation was found between the length of erythrocytes and the concentration of lead, which may show the first symptoms of microcytosis. In comparison to aquatic ecosystems, the biogeochemical factors that influence methylmercury availability in alpine habitats are not yet completely known and require further investigation. Our findings show that birds in alpine terrestrial ecosystems may contain surprisingly high levels of methylmercury. The mercury levels in the feathers of accentors probably indicate that alpine autotrophs make sufficient amounts of mercury available to the terrestrial food web. The blood lead levels of accentors likely approach the threshold level for further hematological effects. We found a clear tendency in erythrocytes to change their shape from ellipsoid to smaller and rounder with increasing amounts of lead in their blood. The shape of bird erythrocytes appears to be a very sensitive indicator of critical levels of lead in the alpine environment.

Dietary patterns, bone lead and incident coronary heart disease among middle-aged to elderly men

BackgroundMost absorbed lead ends up in the bone, where it can be measured as a biomarker of cumulative exposure, elevations of which have been shown to predict a higher risk of coronary heart disease (CHD). Knowledge about the role of dietary patterns is critical to the development of effective interventions for the cardiovascular toxicity of cumulative lead exposure. Methods594 men, free of CHD at baseline, were followed from August 1991 to June 2011 in the Normative Aging Study. Bone lead concentrations were measured by K-shell-X-ray fluorescence. Dietary patterns were identified using principal components analysis. Two dietary patterns were identified: a ‘prudent’ pattern characterized by high intake of fruit, vegetables, legumes, tomatoes, poultry, and seafood; and a ‘Western’ pattern, with high intake of red meat, processed meat, refined grains, high-fat dairy products, high-energy drinks, fries, butter and eggs. Cox proportional hazard models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for incident CHD. Effect modification on the multiplicative scale was examined through cross-product interaction terms. Results137 men developed incident CHD events during 5071 person-years of follow-up. After adjusting for age, body mass index, total energy intake, smoking status, total cholesterol to high-density lipoprotein ratio, education and occupation, an HR of incident CHD was 1.64 (95% CI: 1.27–2.11) with each doubling in patella lead concentration in the low prudent diet group (< median prudent score); and the HR decreased to 1.07 (95% CI: 0.86–1.34) in the high prudent diet (≥ median prudent score) (p-for-interaction = 0.01), suggesting protective effects of prudent diet against lead-related CHD. By contrast, the association between tibia lead and CHD was non-significantly larger in the low Western diet group (HR = 1.43, 95% CI: 1.14–1.80) compared with the high Western diet group (HR = 1.08, 95% CI: 0.86–1.34) (p-for-interaction = 0.06). No significant effect modifications were detected by Western diet in the patella lead-CHD association and by prudent diet in the tibia lead-CHD association. ConclusionsPrudent diet may reduce the risk of development of CHD in relation to patella lead. However, these findings need to be interpreted with caution, given the modest sample size.

The Effect of Prenatal Bone Lead Concentrations on Prepulse Inhibition: A Prospective Study of Mexican Children

Background: An important concern is the toxic legacy of prenatal lead exposure. During pregnancy, maternal skeletal bone lead from earlier exposures mobilizes and crosses placental barriers placing...

Acute and Chronic Lead Exposure in Four Avian Scavenger Species in Switzerland.

Despite irrefutable evidence of its negative impact on animal behaviour and physiology, lethal and sublethal lead poisoning of wildlife is still persistent and widespread. For scavenging birds, ingestion of ammunition, or fragments thereof, is the major exposure route. In this study, we examined the occurrence of lead in four avian scavengers of Switzerland and how it differs between species, regions, and age of the bird. We measured lead concentration in liver and bone of the two main alpine avian scavengers (golden eagle Aquila chrysaetos and bearded vulture Gypaetus barbatus) over the entire area of the Swiss Alps and two of the main avian scavengers occurring in the lowlands of Switzerland (red kite Milvus milvus and common raven Corvus corax). Of those four species, only the bearded vulture is an obligate scavenger. We found that lead burdens in the two alpine avian scavengers were higher than those found for the same species elsewhere in Europe or North America and reached levels compatible with acute poisoning, whereas lead burdens of the two lowland avian scavengers seemed to be lower. Several golden eagles, but only one red kite with abnormally high bone lead concentrations were found. In all four species, a substantial proportion of birds had elevated levels which presumably represent recent (liver lead levels) or past (bone lead levels) uptake of sublethal doses of lead.

A microbeam grazing-incidence approach to L-shell x-ray fluorescence measurements of lead concentration in bone and soft tissue phantoms

Objective: L-shell x-ray fluorescence (LXRF) is a non-invasive approach to lead (Pb) concentration measurements in the human bone. The first studies were published in the early 1980s. In the same period the K-shell x-ray fluorescence (KXRF) method using a Cd-109 radionuclide source was developed and later improved and refined. Lower sensitivity and calibration difficulties associated with the LXRF method led the KXRF to be the most adopted method for in vivo human bone Pb studies. In the present study a microbeam-based grazing-incidence approach to Pb LXRF measurements was investigated. Approach: The microbeam produced by an integrated x-ray tube and polycapillary x-ray lens (PXL) unit was used to excite cylindrical plaster-of-Paris (poP) bone phantoms doped with Pb in seven concentrations: 0, 8, 16, 29, 44, 59, and 74 µg g−1. Two 1 mm- and 3 mm-thick cylindrical shell soft tissue phantoms were made out of polyoxymethylene (POM) plastic. Three bone-soft tissue phantom sets corresponding to the 0, 1, and 3 mm POM thickness values resulted. Each phantom was placed between the microbeam and the detector; its position was controlled using a positioning stage. Small steps (0.1–0.5 mm) and short 30 s x-ray spectra acquisitions were used to find the optimal phantom position according to the maximum observed Sr Kα peak height. At the optimal geometry, five 180 s x-ray spectra were acquired for each phantom set. Calibration lines were obtained using the fitted peak heights of the two observed Pb Lα and Pb Lβ peaks. Main results: The lowest detection limit (DL) values were (2.9 ± 0.2), (4.9 ± 0.3), and (23 ± 3) µg g−1, respectively. The order of magnitude of the absorbed radiation dose in the POM plastic for the 180 s irradiation was estimated to be <1 mGy. Significance: The results are superior to a relatively recently published LXRF phantom study and show promise for future designs of in vivo LXRF measurements.

The decrease in population bone lead levels in Canada between 1993 and 2010 as assessed by in vivo XRF

Objective and Approach: A study, conducted in Toronto, Canada, between 2009 and 2011, measured the bone lead concentrations of volunteers aged 1–82 years using in vivo x-ray fluorescence (XRF) technology. Main results: Bone lead levels were lower compared to Ontario in vivo XRF studies from the early 1990s. In adults, the slope of tibia lead content versus age was reduced by 36–56%, i.e. bone lead levels for a given age group were approximately half compared to the same age group 17 years prior. Further, bone lead levels of individuals fell over that time period. In 2010, an average person aged 57 years had a bone lead level approximately 1/3 less than their bone lead level age 40 years in 1993. Using this data, the half-lives of lead in the tibia were estimated as 7–26 years. Tibia lead levels were found to be low in children. The reduction in bone tibia content in children was not significant (p = 0.07), but using data from additional north eastern US studies, there is evidence that childhood tibia stores are lower than in the 1990s. Significance: In vivo XRF analysis shows that there has been a reduction in the level of lead in bone in Canada over the last two decades. Public health measures have been very successful in reducing ongoing exposure to lead and in reducing bone lead stores.

A Western Diet Pattern Is Associated with Higher Concentrations of Blood and Bone Lead among Middle-Aged and Elderly Men

Background: Little is known about the effects of overall dietary pattern on lead concentration.Objective: We examined the association of overall dietary patterns, derived from a semiquantitative food frequency questionnaire, with bone and blood lead concentrations.Methods: These longitudinal analyses included mostly non-Hispanic white, middle-aged-to-elderly men from the Veterans Affairs Normative Aging Study. Long-term lead exposures were measured as tibia and patella lead concentrations by using K-shell-X-ray fluorescence. Short-term lead exposures were measured as blood lead concentrations by using graphite furnace atomic absorption spectroscopy. Dietary pattern scores were derived by using factor analysis. Linear mixed-effects models were utilized to predict blood lead concentrations among 983 men, aged 44-92 y at baseline, with a total of 3273 observations (during 1987-2008). We constructed linear regression models to determine the relations between dietary patterns and bone lead concentrations among 649 participants with an age range of 49-93 y.Results: Two major dietary patterns were identified: a prudent dietary pattern, characterized by high intakes of fruit, legumes, vegetables, whole grains, poultry, and seafood; and a Western dietary pattern, characterized by high intakes of processed meat, red meat, refined grains, high-fat dairy products, French fries, butter, and eggs. After adjusting for age, smoking status, body mass index, total energy intake, education, occupation, neighborhood-based education and income level, men in the highest tertile of the Western pattern score (compared with the lowest) had 0.91 μg/dL (95% CI: 0.41, 1.42 μg/dL) higher blood lead, 5.96 μg/g (95% CI: 1.76, 10.16 μg/g) higher patella lead, and 3.83 μg/g (95% CI: 0.97, 6.70 μg/g) higher tibia lead. No significant association was detected with the prudent dietary pattern in the adjusted model.Conclusions: These findings suggest that the Western diet is associated with a greater lead body burden among the middle-aged-to-elderly men. More studies are needed to examine the underlying mechanisms by which dietary patterns are associated with lead concentrations.

Noninvasive Determine Lead Poisoning Biomarker for Human Body—Design and Manufacture on Innovated New-XRF Analyzer of Bone Lead

This research introduces an important noninvasive technique which is In vivo measurement of human body bone lead. It makes use of the miniature X tube emitting X-ray through sebum to stimulate the characteristic X fluorescence at the position of tibia under its surface about 1 ～ 1.5 mms. The characteristic X fluorescence which express bone lead content and asking for help from Si-PIN detector and M.C.A analysis system to output a bone lead density d. This technique use the relative functions between sebum thick t and spectrum- unfolding area for bone lead peak. The Compton scatter integral value C could represent sebum thick. It will be calculated the lead content of tibia with ppm .The experiment of this instrument measured 52 data gained by volunteers. This measurement results with other measuring results by international researches are mutually fits together. Thus it is credible that the N-XRF instrument can be possible in vivo to measure bone lead in human body.

Age and sex influence on bone and blood lead concentrations in a cohort of the general population living in Toronto

Objective: To study the age and sex influence on bone and blood lead concentrations in a cohort of the general population living in Toronto.Approach: A 109Cd K x-ray fluorescence (KXRF) measurement system was used from 2009 to 2011 in a study that measured the bone lead (Pb) concentration of 263 environmentally exposed individuals residing in Toronto, Ontario, Canada. Tibia (cortical bone) and calcaneus (trabecular bone) lead contents were measured in 134 males and 129 females between 1 and 82 years of age. Whole blood Pb concentration was measured by TIMS (thermal ionization mass spectrometer). Tibia (Ti) and calcaneus (Cal) Pb were examined versus the age of participants, taking into account uncertainties in bone Pb measurement values.Main results: No significant sex differences were observed in any of the age categories. Participants older than 50 years of age demonstrated the highest concentrations of Pb in their blood, tibia, and calcaneus bones.Significance: In most of the previous publications, uncertainty was not considered in the regression model of bone Pb and age. However, in this paper, we adjusted the bone Pb values for the uncertainty level. This had a significant influence in regression models of bone Pb and thus we recommend that uncertainty be considered in future studies.

Longitudinal associations of age and prenatal lead exposure on cortisol secretion of 12-24 month-old infants from Mexico City.

BackgroundCortisol has functions on homeostasis, growth, neurodevelopment, immune function and the stress response. Secretion follows a diurnal rhythm that mediates these processes. Our objective was to examine the association between prenatal lead exposure and infant diurnal cortisol rhythms.MethodsWe measured infant cortisol rhythms in saliva collected repeatedly over 2 days at either 12 (n = 255) or 18–24 (n = 150) months of age. Prenatal lead exposure was assessed by measuring maternal pregnancy blood lead levels and early postnatal maternal bone lead content. We analyzed age-specific basal secretion and the association between trimester-specific and cumulative lead exposure with a) change in total diurnal cortisol and b) the shape of the cortisol curve across the length of the day.ResultsOur results showed age related differences in salivary cortisol secretion and an age dependent association with maternal lead exposure. In age-stratified models we saw an inverse association between lead and cortisol levels in 12-month-old infants and a positive association for 18–24-month-old infants. For the 12-month-old infants 2nd-trimester-lead ≥10 μg/dL was associated with 40 % lower cortisol levels (95 % CI (−57, −16)) and a significant change in the shape of the cortisol curve (p = 0.01), compared to infants with low blood lead levels (<5 μg/dL).ConclusionsBasal cortisol secretion changes with age. Increased early gestation lead exposure alters diurnal cortisol rhythms and the association is modified by infant age, perhaps representing an early maturation of cortisol homeostasis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0124-1) contains supplementary material, which is available to authorized users.