Association of Blood Lead (Pb) and Plasma Homocysteine: A Cross Sectional Survey in Karachi, Pakistan

Yakub, Mohsin; Iqbal, Mohammad Perwaiz

doi:10.1371/journal.pone.0011706

Cited by 31 publications

(31 citation statements)

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“…A cross-sectional study among adults in Pakistan with average blood lead concentrations 11.7 μg/dL found greater changes in homocysteine 4.6% (95% CI: 2.6, 4.8%) per IQR increase (~8 μg/dL) in lead concentrations [6]. In contrast, lead exposures in our study were about 10 μg/dL lower.…”

Section: Discussioncontrasting

confidence: 77%

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

et al. 2017

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Background: To examine the relationship between cadmium, lead, and mercury concentrations with high-sensitivity C-reactive protein (hs-CRP) and homocysteine in women. Methods: Metals were measured at enrollment in whole blood. Homocysteine and hs-CRP were measured in one (N = 9) or two (N = 250) menstrual cycles up to 3 and 8 times per cycle, respectively. Linear mixed models with inverse probability of exposure weights to account for time varying confounding were used and models were stratified by dietary and serum vitamin status (dietary: vitamin B 6 , B 12 , folate; serum: folate). Results: Geometric mean (95% confidence interval (CI)) concentrations for cadmium, lead, and mercury were 0.29 (0.26-0.31) μg/L, 0.91 (0.86-0.96) μg/dL, and 1.05 (0.93-1.18) μg/L, respectively. Lead was associated with increased homocysteine (0.08; 95% CI: 0.01, 0.15) and this persisted among those in the lower three quartiles of consumption of vitamin B 6 , B 12 , folate, and serum folate but was not significant among those in the upper quartile. No associations were observed between metals and hs-CRP. Conclusions: Blood lead was associated with increased homocysteine in a cohort of healthy, premenopausal women but these associations did not persist among those consuming ≥75th percentile of essential micronutrients. Cadmium, lead, and mercury were not associated with hs-CRP concentrations.

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Section: Discussioncontrasting

confidence: 77%

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

et al. 2017

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“…A systematic random sampling was adopted as described in a previous publication [6]. Healthy individuals were screened by community health workers who were trained to collect demographic and clinical information.…”

Section: Methodsmentioning

confidence: 99%

Polymorphisms in MTHFR, MS and CBS Genes and Homocysteine Levels in a Pakistani Population

et al. 2012

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BackgroundHyperhomocysteinemia (>15 µmol/L) is highly prevalent in South Asian populations including Pakistan. In order to investigate the genetic determinants of this condition, we studied 6 polymorphisms in genes of 3 enzymes - methylenetetrahydrofolate reductase (MTHFR; C677T; A1298C), methionine synthase (MS; A2756G), cystathionine-β-synthase (CBS; T833C/844ins68, G919A) involved in homocysteine metabolism and investigated their interactions with nutritional and environmental factors in a Pakistani population.Methodology/Principal FindingsIn a cross-sectional survey, 872 healthy adults (355 males and 517 females; age 18–60 years) were recruited from a low-income urban population in Karachi. Fasting venous blood was obtained and assessed for plasma/serum homocysteine; folate, vitamin B12, pyridoxal phosphate and blood lead. DNA was isolated and genotyping was performed by PCR-RFLP (restriction-fragment-length- polymorphism) based assays. The average changes in homocysteine levels for MTHFR 677CT and TT genotypes were positive [β(SE β), 2.01(0.63) and 16.19(1.8) µmol/L, respectively]. Contrary to MTHFR C677T polymorphism, the average changes in plasma homocysteine levels for MS 2756AG and GG variants were negative [β(SE β), −0.56(0.58) and −0.83(0.99) µmol/L, respectively]. The average change occurring for CBS 844ins68 heterozygous genotype (ancestral/insertion) was −1.88(0.81) µmol/L. The combined effect of MTHFR C677T, MS A2756G and CBS 844ins68 genotypes for plasma homocysteine levels was additive (p value <0.001). Odds of having hyperhomocysteinemia with MTHFR 677TT genotype was 10-fold compared to MTHFR 677CC genotype [OR (95%CI); 10.17(3.6–28.67)]. Protective effect towards hyperhomocysteinemia was observed with heterozygous (ancestral/insertion) genotype of CBS 844ins68 compared to homozygous ancestral type [OR (95% CI); 0.58 (0.34–0.99)]. Individuals with MTHFR 677CT or TT genotypes were at a greater risk of hyperhomocysteinemia in folate and vitamin B12 deficiencies and high blood lead (p value <0.05) level.ConclusionsGene polymorphism (especially MTHFR C677T transition), folate and vitamin B12 deficiencies, male gender and high blood lead level appear to be contributing towards the development of hyperhomocysteinemia in a Pakistani population.

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“…Ghauri et al (2007) has established baseline levels in major urban cities including Karachi and reported TSP concentration at 410 µg m -3 in Karachi. Yakub and Iqbal (2010) studied the risk of hyperhomocysteinemia due to lead (Pb) level in blood of a low income urban population in Karachi. Shahid et al (2016) reported chemical characterization of PM 10 and PM 2.5 that included Elemental Carbon (EC), Organic Carbon (OC), soluble ions, anyhdro sugars and mass closure.…”

Section: Introductionmentioning

confidence: 99%

Source Apportionment of PM10 at an Urban Site of a South Asian Mega City

Shahid

Alvi

Shahid

et al. 2018

Aerosol Air Qual. Res.

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In the present study, analysis and source apportionment of the elemental composition of PM 10 was conducted in the urban atmosphere of Karachi. Trace elements such as Ni, Ba, Cd, Ca, Mg, Cr, Mn, Fe, Co, Cu, Sr and Ti were measured. The PM 10 concentration ranged from 255 μg m -3 to 793 μg m -3 , with an average of 438 ± 161 μg m -3 . Among the various elements analyzed, concentrations of Ca, Al and Fe were the highest (> 10000 ng m -3 ), followed by Mg and S (> 1000 ng m -3 ). Elements such as Zn, P, Cu, Pb, Mn, Ti, Sr and Ba demonstrated medium concentrations (> 100 ng m -3 ), whereas the lowest concentrations were found for elements such as Cr, Ni and Se (> 10 ng m -3 ). The Positive Matrix Factorization (PMF) model identified five possible factors that contributed to PM 10 , namely, biomass burning, coal combustion, resuspended road/soil dust, vehicular emissions and industrial dust. Industrial dust was the highest contributor (23.2%) to PM 10 followed by Biomass burning (23%), Vehicular emissions (22.2%), Coal combustion (21.7%) and Re-suspended dust (9.9%). A strong positive correlation (R 2 = 0.98) was observed between the model predicted PM 10 mass and the gravimetrically measured mass collected on filters.

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Association of Blood Lead (Pb) and Plasma Homocysteine: A Cross Sectional Survey in Karachi, Pakistan

Cited by 31 publications

References 15 publications

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

Blood lead, cadmium and mercury in relation to homocysteine and C-reactive protein in women of reproductive age: a panel study

Polymorphisms in MTHFR, MS and CBS Genes and Homocysteine Levels in a Pakistani Population

Source Apportionment of PM10 at an Urban Site of a South Asian Mega City

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