Prevalence Of Blood Lead Levels Research Articles

An investigation of outpatient children's blood lead level in Wuhan China.

ObjectiveBlood lead levels (BLLs) and possible influencing factors in children in Wuhan China were investigated in order to understand current lead pollution exposure and provide a scientific basis for prevention and policy making.Materials and MethodsBLL data were collected from 15,536 out-patients in Wuhan Children Hospital in 2012 full year. All of them were under 18 years of age (Mean ± SD: 4.32±3.2, 64.4% boys). The BLLs were measured by an atomic absorption spectrometry (BH2100).ResultsThe geometric mean of BLLs for all the subjects was 44.75 µg/L (95%CI: 44.46 µg/L – 45.05 µg/L), much lower than that reported in previous studies. The prevalence of the elevated BLLs (≥ 100 µg/L) in the children tested was 2% in 2012 and the prevalence of BLLs (≥ 50 µg/L) was 44%. Age and sex could be possible influencing factors for BLLs in the children (p<0.001). In addition, the BLLs in different seasons were different (p<0.001).ConclusionsThese results demonstrate that BLLs have significantly decreased in children in Wuhan during recent years. However, we should continuously pay attention to lead pollution and emphasize that prevention is much more important than treatment for controlling children's BLLs.

Blood lead concentrations in sub‐Saharan African children below 6 years: systematic review

To assess the geometric mean of blood lead levels in children aged below 6years living in sub-Saharan Africa. Search strategies were developed in MEDLINE, Web of Science and Google scholar system, supplemented by screening of references from included papers and review articles. Studies including children younger than 6years residing in sub-Saharan Africa (SSA) were eligible. The studies were assessed for quality of methods for blood collection, for participants' recruitment and for quality control for lead analyses. Data were extracted and synthetised by estimating the mean weighted by sample size. A total of 11148 published papers were identified with only 16 studies conducted in SSA. Only nine of them were relevant of inclusion criteria. The weighted mean of blood lead levels was 13.1μg/dl. Five of included studies were classified as being less likely to present selection bias, having performed venipuncture and adequate quality control for lead analyses. The weighted mean from analyses involving only these studies was 16.2μg/dl. Six of the included studies reported the prevalence of blood lead levels ≥10μg/dl; levels ranged from 7.0% to 70.9%. Only one study reported the prevalence of blood lead levels ≥5μg/dl (50%). The geometric mean of blood lead levels in sub-Saharan African children is still elevated relative to the US children. The new standard from the Centers for Disease Control and Prevention (5μg/dl) implies that important efforts should be directed towards the initiation (or reinforcement) of prevention programmes and thorough research studies in sub-Saharan Africa.

Blood lead levels among children aged 0 to 6 years in 16 cities of China, 2004-2008

Background The adverse health effects of lead for children under 6 years are well known. Studies to assess the lead exposure among children in China are small in sample size and lack of national representative data. The aim of this study therefore was to describe blood lead levels and identify risk factors for lead exposure among children aged 0 to 6 years living in 16 cities in China. Methods We analyzed data from blood lead levels surveillance in China carried out in 16 large cities between 2004 and 2008. A stratified clustered random sampling strategy was used. A total of 69 968 children aged 0 to 6 years were included. We conducted multiple Logistic regression analyses to explore risk factors to high blood lead level. Results The geometric mean blood lead level of the children was 4.50 μg/dl (median: 4.90 μg/dl; IQR: 3.20-7.00 μg/dl). Overall prevalence of blood lead level ≥10.00 μg/dl among 0- to 6-year-old children was 7.57%. But the proportion of blood lead level ≥5.00 but &lt;10.00 μg/dl was 42.12%. Blood lead levels were significantly higher in boys (4.63 μg/dl) than in girls (4.35 μg/dl) (P &lt;0.0001). The geometric mean blood lead levels and prevalence of blood lead level ≥10.00 μg/dl increased with age (P &lt;0.0001 for the two trends). After controlling for sociodemographic, dietary and behavior factors, multivariable analysis indicated that lower maternal education, male gender, younger age, often biting pencil or/and toys, walking or playing for long time on the street, not washing hands before eating are major risk factors for higher lead levels. Conclusions The blood lead levels among Chinese children in urban areas are lower than previous studies but close to those of developed countries. However, children with low lead exposure account for almost half and the sociodemographic factors (age, male sex, and low mother education level) continue to be associated with higher blood lead levels.

Association between blood lead levels and environmental exposure among Saudi schoolchildren in certain districts of Al-Madinah

IntroductionBoth occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries. When humans are exposed to high levels of lead, there is damage to almost all organs and organ systems (most importantly, the central nervous system, kidneys, and blood), which often culminates in death.ObjectiveTo estimate the prevalence of blood lead levels (BLLs) and to identify the sources of environmental exposure and potential risk factors for elevated BLLs among Saudi schoolchildren.MethodsA cross-sectional survey was conducted from March to May 2010. The study population included 557 Saudi school students of both sexes. A multistage random sampling technique was used. Information about socioeconomic status, house and school construction, and parents’ education and employment was collected using questionnaires. Lead was analyzed in a blood sample using an atomic absorption technique and hemoglobin was measured using a Sysmex hematological analyzer.ResultsThe mean BLL was 4.94 ± 3.38 μg/dL (range 0.45–26.3 μg/dL). A total of 19% had BLLs <1.0 μg/dL, 16% had BLLs <2.5 μg/dL, 15% had BLLs <5.0 μg/dL, 20% had BLLs <7.5 μg/dL, 25% had BLLs <10.0 μg/dL, and about 6% had BLLs >10.0 μg/dL. Analysis of odds by controlling all risk factors (adjusted odds ratio [OR]) that affect BLLs (≥10 μg/dL) indicated that using cosmetics (OR = 18.5, confidence interval [CI] = 14.4–19.8), putting colored toys in mouth (OR = 15.7, CI = 3.6–16.2), eating canned food (OR = 9.8, CI = 7.0–10.1), and using newspaper during food preparation (OR = 7.6, CI = 6.3–8.2) are risk factors. There were significant correlations between BLLs and family habits (r = 0.225, P = 0.000), personal habits (r = 0.321, P = 0.000), eating habits (r = 0.128, P = 0.002) and school building characteristics (r = 0.469, P = 0.000). There was a significant correlation between BLLs and anemia in age group 6 < 12 years (P = 0.000) and age group 12 to less than 18 years, among males (P = 0.000) and females (P = 0.041).ConclusionThe BLLs of children are affected by multiple factors. Female students have higher BLLs and lower hemoglobin concentration than males. The possible sources of lead exposure were use of toothpaste, use of kohl, putting colored toys in the mouth, use of both canned food and canned juice, use of lip gloss in females, and different methods of handling newspaper while preparing food.

Community blood lead survey with emphasis on preschool children following lead dust pollution in Esperance, Western Australia

To assess the impact of airborne lead dust on blood lead levels in residents of Esperance, a regional Western Australian town, with particular reference to preschool children. Following identification of significant airborne lead contamination, residents were notified that a blood lead clinic was available to all, with testing of preschool children encouraged. About 40% (333 children) of the preschool group and about 20% of the remaining population were tested. The main measures were blood lead levels, prevalence of elevated results and comparisons to other Western Australian surveys. In preschoolers, 2.1% (seven children) had blood lead levels exceeding the current 10 μg/dL level of concern. This was not significantly different to two previous community-based surveys elsewhere in Western Australia. However, at a lower cut-off of 5 μg/dL, the prevalence of elevated lead levels was 24.6%, significantly higher than children tested in a previous Western Australian survey. The prevalence of blood lead levels of 10 μg/dL or greater in adults was 1.3% (26 adults), not significantly different from a previous Western Australian survey. The prevalence of preschool children with blood lead levels exceeding the current level of concern was not significantly increased. However, the increased prevalence of children with lead levels at or above 5 μg/dL demonstrates exposure to lead dust pollution. This episode of lead dust contamination highlights the need for strict adherence to environmental controls and effective monitoring processes to ensure the prevention of future events.

BLOOD LEAD LEVELS IN SCHOOLCHILDREN LIVING NEAR TO AN INDUSTRIAL ZONE IN CALI, COLOMBIA: THE SYNERGISTIC ROLE OF SOCIOECONOMIC CONDITION

Background and Aims: In developing countries, distribution of health effects associated to lead sources could be differential, in particular, because greater exposure and susceptibility occur among people with lower socioeconomic condition(SEC). Northern Cali-Colombia limits with a large industrial zone producing steel, batteries and metals. According to previous reports, high concentrations of airborne lead (1.77µg/m3) may reach population living in the area. We determined blood lead levels (BLL) in schoolchildren 6-14 years old exposed to industrial sources of lead and to evaluate the synergistic role of SEC. Methods: A cross-sectional study was conducted in an area exposed to industrial pollutants in northern Cali. A control area was also studied and children in two schools at corresponding study areas were selected. Venous samples (5 mL) were collected in heparinized, evacuated tubes to determine BLL by graphite furnace absorption spectrometry. Using regression models we assessed risk factors for high BLL, controlling for potential confounders and evaluating the potential effect modification of socioeconomic condition. Results: We enrolled 350 schoolchildren, 44.5% living in the exposed area. Schoolchildren in this area had higher BLL (4.7±1.6 vs. 2.9±1.2) and prevalence of BLL •5 µg/dl (44.2% vs. 8.2%, p:0.000) than those in control area. An independent association was found between exposure and BLL •5 µg/dL (OR:16.3; CI95%:6.7-30.1), younger age (OR:2.1; CI95%:1.1-4.1), male gender (OR:;2.7 CI95%:1.4-5.3), lower socioeconomic condition (OR:2.5; CI95%:1.2-5.0), middle/low parent´s attained education (OR:2,3; CI95%:0.97-5.9) and black ethnicity (OR:4.7 IC95%: 1.8-14.9). Additionally, synergistic effects on greater risk of BLL were observed between low socioeconomic condition (P for interaction: 0.000). Conclusions: Residence in an urban area exposed to industrial lead emissions is associated to higher levels of BLL. Socioeconomic conditions and male sex modify observed BLL, with a greater risk of exposure. Given that higher disease susceptibility is also expected among those children, health effects could be potentiated in these children.

Prevalence of Blood Lead Level in Children Living in a Community Exposed by Lead Glazed Ceramics in Michoacan, Mexico

ISEE-0079 Objective: There are many references worldwide on the sources, pathways, risks and health effects of lead exposure in people, and in particular, people who work with lead glazed ceramics. Exposure to several sources of lead is a widespread and serious threat to the health of the children of Michoacan. Our aim is to assess the blood lead levels in children from a community that has produced lead glazed ceramics for four centuries. Material and Methods: 92 children from Santa Fe de la Laguna were tested in October, 2003. The children ranged between the ages of one to 11, and all of them were from families that regularly worked with lead glazed pottery. With the parents’ written permission letter, we obtained capillary blood samples. The blood was then analyzed in the field with portable equipment, provided by the National Institute of Perinatology, from Mexico City. Results: All 92 children had measurable blood lead levels with a range of 6.40 to 65 micrograms per deciliter. The mean was 31.94 with standard deviation of 15.18 and a standard error of 1.59. 95% confidence interval for the mean was 28.78 to of 35.11. Conclusions: Mexican regulations allow levels of up to 10 micrograms per deciliter in children. Above this, there is an increased risk to health. Thus, the future of these children is uncertain. We hope to study more about susceptibility in ethnic groups with genetic polymorphisms to lead and treat with calcium, folic acid and others. We suggest to National Health authorities a strong policy and public health programme to reduce this problem. Disclaimer: These findings and conclusions do not necessarily represent the views of the official institution report.

Blood lead levels in children from the city of La Plata, Argentina. Relationship with iron deficiency and lead exposure risk factors

Environmental exposure to lead and the subsequent poisoning are a main public health concern worldwide. Children have a higher vulnerability to lead toxic effects, and many reports have shown the association between iron deficiency and lead poisoning. In Argentina, reports about lead levels in children are scarce. Our aims were to assess blood lead levels in children and determining their relationship with iron deficiency and known lead exposure risk factors. We performed a cross-sectional study in a sample of 93 children (age range, 6 months to 5 years) receiving care at La Plata Children s Hospital. A social and environmental survey was done, and blood lead, hemoglobin and ferritin levels were assessed. Geometric mean blood lead level was 4.26 microg/dl (95% CI, 3.60-5.03); prevalence of blood lead levels >or=10 microg/dl was 10.8%. Higher blood lead levels were found in children living in households with lead-handling contaminating activities (6.74 vs. 3.78 microg/dl; p= 0.005) and in very low-income households (5.68 vs. 3.71 microg/ dl; p= 0.020). The presence of blood lead levels >or=10 microg/dl was strongly associated with iron deficiency (OR 5.7; 95% CI: 1.34-23.41) and with lead-handling activities at home (OR 4.8; 95% CI: 1.12-20.16). The prevalence of blood lead levels >or=10 microg/dl is a matter of concern in the population studied. Iron deficiency and development of lead-handling activities at home were the risk factors associated with high blood lead levels.

Making the Needed Linkages and Economic Case for Continued Lead-Paint Abatement

Making the Needed Linkages and Economic Case for Continued Lead-Paint Abatement

The Prevalence of Blood Lead Levels ≥5μg/dl among 1 to 21 Year Old U.S. Population and Trends from 1988–1994 through 1999–2002

Elevated blood lead in children is defined as ≥10ug/dl. In light of data suggesting adverse health effects at blood lead levels (PbB) <10ug/dl, lowering the current definition has been recommended. To ascertain the population level impact of such a change, we calculated the prevalence and distribution of PbB ≥5μg/dl in 1 to 21 year old population in the United States. Furthermore, we characterized changes in PbB between 1988–1994 and 1999–2002. We analyzed data from the National Health and Nutrition Examination Survey (NHANES) III (n=10,755) and NHANES 1999–2002 (n=8,013). Between 1988–1994 and 1999–2002, the geometric mean PbB declined from 2.88μg/dl to 1.94μg/dl in children 1 to 5 years, 1.80 μg/dl to 1.36μg/dl in children 6 to 11 years, and 1.24μg/dl to 1.02μg/dl in children and adolescents 12 to 21 years of age. Also, the prevalence of PbB ≥5μg/dl declined from 25.7% to 8.8%, 12.8% to 3.0%, and 7.5% to 1.2% in these age groups, respectively. In 1999–2002, a disproportionately higher prevalence of PbB ≥5μg/dl was present among children 1 to 5 and 6 to 11 years old who were non-Hispanic blacks, had lower household income, were not home owners, and lived in older housing. Among 12 to 21 year olds, having lower income levels, male sex, and no health insurance were each associated with a higher prevalence of PbB ≥5μg/dl. Despite an overall decline in PbB, a substantial proportion of children (approximately 2.4 million) may be at risk for adverse health effects from lead exposure.

Iron Fortification Reduces Blood Lead Levels in Children in Bangalore, India

Chronic lead poisoning and iron deficiency are concentrated in urban children from lower socioeconomic strata, and both impair neurocognitive development. Our study objective was to determine if iron fortification reduces blood lead levels in urban, lead-exposed, iron-deficient children in Bangalore, India. A randomized, double-blind, controlled school-based feeding trial was done in 5- to 13-year-old iron-deficient children (n = 186). At baseline, a high prevalence of lead poisoning was found in the younger children. Subsequently, all 5- to 9-year-old children participating in the trial (n = 134) were followed to determine if iron fortification would affect their blood lead levels. Children were dewormed and fed 6 days/week for 16 weeks either an iron-fortified rice meal (approximately 15 mg of iron per day as ferric pyrophosphate) or an identical control meal without added iron. Feeding was directly supervised and compliance monitored. Hemoglobin, serum ferritin, C-reactive protein, transferrin receptor, zinc protoporphyrin, and blood lead concentrations were measured. The prevalence of iron deficiency was significantly reduced in the iron group (from 70% to 28%) compared with the control group (76% to 55%). There was a significant decrease in median blood lead concentration in the iron group compared with the control group. The prevalence of blood lead levels > or =10 microg/dL was significantly reduced in the iron group (from 65% to 29%) compared with the control group (68% to 55%). Our findings suggest providing iron in a fortified food to lead-exposed children may reduce chronic lead intoxication. Iron fortification may be an effective and sustainable strategy to accompany environmental lead abatement.

Statewide assessment of lead poisoning and exposure risk among children receiving Medicaid services in Alaska.

Lead poisoning is a well-recognized public health concern for children living in the United States. In 1992, Health Care Financing Administration (HCFA) regulations required lead poisoning risk assessment and blood lead testing for all Medicaid-enrolled children ages 6 months to 6 years. This study estimated the prevalence of blood lead levels (BLLs) >/=10 microg/dL (>/=0.48 micromol/L) and the performance of risk assessment questions among children receiving Medicaid services in Alaska. Measurement of venous BLLs in a statewide sample of children and risk assessment using a questionnaire modified from HCFA sample questions. Eight urban areas and 25 rural villages throughout Alaska. Nine hundred sixty-seven children enrolled in Medicaid, representing a 6% sample of 6-month- to 6-year-old Alaska children enrolled in Medicaid. Determination of BLL and responses to verbal-risk assessment questions. BLLs ranged from <1 microg/dL (<0.048 micromol/L) to 21 microg/dL (1.01 micromol/L) (median, 2.0 microg/dL or 0.096 micromol/L). The geometric mean BLLs for rural and urban children were 2.2 microg/dL (0.106 micromol/L) and 1.5 microg/dL (0.072 micromol/L), respectively. Six (0.6%) children had a BLL >/=10 microg/dL; only one child had a BLL >/=10 microg/dL (11 microg/dL or 0.53 micromol/L) on retesting. Children whose parents responded positively to at least one risk factor question were more likely to have a BLL >/=10 microg/dL (prevalence ratio = 3.1; 95% confidence interval = 0.4 to 26.6); the predictive value of a positive response was <1%. In this population, the prevalence of lead exposure was very low (0.6%); only one child tested (0.1%) maintained a BLL >/=10 microg/dL on confirmatory testing; no children were identified who needed individual medical or environmental management for lead exposure. Universal lead screening for Medicaid-enrolled children is not an effective use of public health resources in Alaska. Our findings identify an example of the importance in considering local and regional differences when formulating screening recommendations and regulations, and continually reevaluating the usefulness of federal regulations.

A pilot study of take-home lead exposure in New Jersey.

Studies in various industries have found an association between worker exposure to lead and elevated blood lead levels in workers' children, but the magnitude of this problem is unknown. In an effort to characterize this problem further, a pilot study was undertaken to obtain blood lead levels of children of lead-exposed workers with elevated blood lead levels who had been reported by laboratories to the New Jersey Department of Health. Fifteen workers' families participated in this study, including 28 children. Thirty-two percent of the children were found to have blood lead levels > or = 10 micrograms/dl, the level of concern set by the Centers for Disease Control and Prevention for medical monitoring. This finding is in contrast to population-based data collected from the Third National Health and Nutrition Survey, where the overall prevalence of blood lead levels > or = 10 micrograms/dl was only 4.5%.

Childhood Lead Poisoning in 1994

To the Editor. —As described in the July 27, 1994, issue of JAMA , 1,2 the marked decrease in blood lead levels of the US population between 1976 and 1991, documented by NHANES III, is a tribute to effective preventive health measures, mainly the removal of lead from gasoline, cans, and paint. From 1976 to 1991, the mean blood lead level in the United States decreased more than fourfold, with a 10-fold decrease in prevalence of blood lead levels ≥0.48 μmol/L (≥10 μg/dL) among children aged 1 to 5 years, those most at risk. These results confirm clinical observations during the past 20 years—that symptomatic lead poisoning is disappearing among US children. This good news has been counterbalanced by claims that blood lead levels previously considered safe (

The Decline in Blood Lead Levels in the United States

To describe trends in blood lead levels for the US population and selected population subgroups during the time period between 1976 and 1991. Two nationally representative cross-sectional surveys and one cross-sectional survey representing Mexican Americans in the southwestern United States. Participants in two national surveys that included blood lead measurements: the second National Health and Nutrition Examination Survey, 1976 to 1980 (n = 9832), and phase 1 of the third National Health and Nutrition Examination Survey, 1988 to 1991 (n = 12,119). Also, Mexican Americans participating in the Hispanic Health and Nutrition Examination Survey, 1982 to 1984 (n = 5682). The mean blood lead level of persons aged 1 to 74 years dropped 78%, from 0.62 to 0.14 mumol/L (12.8 to 2.8 micrograms/dL). Mean blood lead levels of children aged 1 to 5 years declined 77% (0.66 to 0.15 mumol/L [13.7 to 3.2 micrograms/dL]) for non-Hispanic white children and 72% (0.97 to 0.27 mumol/L [20.2 to 5.6 micrograms/dL]) for non-Hispanic black children. The prevalence of blood lead levels 0.48 mumol/L (10 micrograms/dL) or greater for children aged 1 to 5 years declined from 85.0% to 5.5% for non-Hispanic white children and from 97.7% to 20.6% for non-Hispanic black children. Similar declines were found in population subgroups defined by age, sex, race/ethnicity, income level, and urban status. Mexican Americans also showed similar declines in blood lead levels of a slightly smaller magnitude over a shorter time. The results demonstrate a substantial decline in blood lead levels of the entire US population and within selected subgroups of the population. The major cause of the observed decline in blood lead levels is most likely the removal of 99.8% of lead from gasoline and the removal of lead from soldered cans. Although these data indicate major progress in reducing lead exposure, they also show that the same sociodemographic factors continue to be associated with higher blood lead levels, including younger age, male sex, non-Hispanic black race/ethnicity, and low income level. Future efforts to remove other lead sources (eg, paint, dust, and soil) are needed but will be more difficult than removing lead from gasoline and soldered cans.

Neonatal Genital Prolapse

In Reply.— I don9t dislike lead screening, Dr Goldman; I just dislike the method of lead screening recommended in the October 1991 report of the CDC Advisory Committee on Childhood Lead Poisoning Prevention, of which you were a member.1 Dr Goldman has objected to my statement2 that for her to report a 67% prevalence of blood lead levels (BLL) ≥10 µg/dL and omit the fact that the testing method was inaccurate was a serious omission. Dr Goldman has stated that she omitted this important information because it didn9t fit within the content of our brief report.

Lead Toxicity: Current Concerns

Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has been the demonstration that blood lead (PbB) levels of 10-15 micrograms/dL in newborn and very young infants result in cognitive and behavioral deficits. Further support for this observation is being obtained by prospective or longitudinal studies presently in progress. The mechanism(s) for the central nervous system effects of lead is unclear but involve lead interactions within calcium-mediated intracellular messenger systems and neurotransmission. Effects of low-level lead exposure on blood pressure, particularly in adult men, may be related to the effect of lead on calcium-mediated control of vascular smooth muscle contraction and on the renin-angiotensin system. Reproductive effects of lead have long been suspected, but low-level effects have not been well studied. Whether lead is a carcinogen or its association with renal adenocarcinoma is a consequence of cystic nephropathy is uncertain. Major risk factors for lead toxicity in children in the United States include nutrition, particularly deficiencies of essential metals, calcium, iron, and zinc, and housing and socioeconomic status. A goal for the year 2000 is to reduce prevalence of blood lead levels exceeding 15 micrograms/dL.

Lead toxicity: current concerns.

Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has been the demonstration that blood lead (PbB) levels of 10-15 micrograms/dL in newborn and very young infants result in cognitive and behavioral deficits. Further support for this observation is being obtained by prospective or longitudinal studies presently in progress. The mechanism(s) for the central nervous system effects of lead is unclear but involve lead interactions within calcium-mediated intracellular messenger systems and neurotransmission. Effects of low-level lead exposure on blood pressure, particularly in adult men, may be related to the effect of lead on calcium-mediated control of vascular smooth muscle contraction and on the renin-angiotensin system. Reproductive effects of lead have long been suspected, but low-level effects have not been well studied. Whether lead is a carcinogen or its association with renal adenocarcinoma is a consequence of cystic nephropathy is uncertain. Major risk factors for lead toxicity in children in the United States include nutrition, particularly deficiencies of essential metals, calcium, iron, and zinc, and housing and socioeconomic status. A goal for the year 2000 is to reduce prevalence of blood lead levels exceeding 15 micrograms/dL.