Cadmium and lead exposure and risk of cataract surgery in U.S. adults.
ABSTRACT: Cataract is a major cause of visual dysfunction and the leading cause of blindness. Elevated levels of cadmium and lead have been found in the lenses of cataract patients, suggesting these metals may play a role in cataract risk. This study aimed to examine the associations of blood lead, blood cadmium and urinary cadmium with cataract risk. We identified 9763 individuals aged 50 years and older with blood lead and cadmium levels, and a randomly selected subgroup of 3175 individuals with available urinary cadmium levels, from the National Health and Nutrition Examination Surveys (NHANES) from 1999 to 2008 (mean age=63years). Participants were considered to have cataract if they self-reported prior cataract surgery in NHANES's vision examination. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using survey logistic regression models. We identified 1737 cataract surgery cases (the weighted prevalence=14.1%). With adjustment for age, race/ethnicity, gender, education, diabetes mellitus, body mass index, cigarette smoking (serum cotinine and pack-years) and urine hydration, every 2-fold increase in urinary cadmium was associated with a 23% higher risk of cataract surgery (OR=1.23, 95% CI: 1.04, 1.46, p=0.021). We found no associations of cataract surgery with blood cadmium (OR=0.97, 95% CI: 0.89, 1.07) and blood lead (OR=0.97, 95% CI: 0.88, 1.06). Mediation analysis showed that for the smoking-cadmium-cataract pathway, the ratio of smoking's indirect effect to the total effect through cadmium was more than 50%. These results suggest that cumulative cadmium exposure may be an important under-recognized risk factor for cataract. However, these findings should be interpreted with a caution because of inconsistent results between urinary cadmium and blood cadmium.
Project description:Age-related macular degeneration (AMD) is a complex disease resulting from the interplay of genetic predisposition and environmental exposures, and has been linked to oxidative stress and inflammatory mechanisms. Lead and cadmium can accumulate in human retinal tissues and may damage the retina through oxidative stress, and may thereby play a role in the development of AMD. We examined associations between blood lead, blood cadmium, and urinary cadmium concentrations and the presence of AMD in 5390 participants aged 40 years and older with blood lead and blood cadmium measures and a subsample of 1548 with urinary cadmium measures in the 2005-2008 National Health and Nutrition Examination Surveys. AMD was identified by grading retinal photographs with a modification of the Wisconsin Age-Related Maculopathy Grading System. The weighted prevalence of AMD was 6.6% (n=426). Controlling for age, gender, race/ethnicity, education and body mass index, adults in the highest blood cadmium quartile had higher odds of AMD compared to the lowest quartile (odds ratio [OR], 1.56; 95% CI, 1.02-2.40), with a significant trend across quartiles (p-trend=0.02). After further adjustment for pack-years of cigarette smoking, estimates were somewhat attenuated (OR, 1.43; 95% CI, 0.91-2.27; p-trend=0.08). Similar associations were found with urinary cadmium. The association between urinary cadmium and AMD was stronger in non-Hispanic whites (NHW) than in non-Hispanic blacks (NHB) (OR, 3.31; 95% CI, 1.37-8.01 for levels above versus below the median among NHW; OR,1.45; 95% CI, 0.40-5.32 for levels above versus below the median among NHB; p-interaction=0.03). We found no association between blood lead levels and AMD. Higher cadmium body burden may increase risk of AMD, particularly among non-Hispanic white individuals; however, additional studies are needed before firm conclusions can be drawn.
Project description:American Indian communities are at greater risk of hypertension and cardiovascular disease than the general US population and are exposed to greater cadmium levels. However, cadmium's effect on blood pressure is unclear. This study assesses the association between baseline urinary cadmium and longitudinal changes in blood pressure in American Indian communities. Cadmium was measured in 3047 baseline urine samples from Strong Heart Study participants from three geographic areas. Longitudinal changes in blood pressure across three study visits (1989-1999) were modeled using linear mixed models by baseline log urinary cadmium to creatinine ratio. Hypertension risk was evaluated using interval-censored survival analysis. Higher levels of urinary cadmium at baseline were associated with faster rates of increase in diastolic and systolic blood pressure (P [trend] = .001 and .02, respectively). The estimated change in diastolic and systolic blood pressures per year was 0.18 mm Hg (0.05-0.31) and 0.62 mm Hg (0.37-0.87) in the upper quintile of cadmium level compared with -0.11 mm Hg (-0.24 to 0.02) and 0.21 mm Hg (-0.04 to 0.46) in the lowest, respectively. A one-unit increase in log-transformed urinary cadmium was associated with 10% greater hypertension risk (95% confidence interval: 1.01-1.20). In conclusion, blood pressure of individuals with greater baseline levels of urinary cadmium increased at a faster rate relative to those with lower levels.
Project description:The effect of heavy metals at environmentally relevant concentrations on couple fecundity has received limited study despite ubiquitous exposure. In 2005-2009, couples (n=501) desiring pregnancy and discontinuing contraception were recruited and asked to complete interviews and to provide blood specimens for the quantification of cadmium (?g L(-1)), lead (?g dL(-1)) and mercury (?g L(-1)) using inductively coupled plasma-mass spectrometry. Couples completed daily journals on lifestyle and intercourse along with menstruation and pregnancy testing for women. Couples were followed for 12 months or until pregnant. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated adjusting for age, body mass index, cotinine, and serum lipids in relation to female then male exposures. FORs <1 denote a longer time to pregnancy. In adjusted models, reduced FORs were observed for both female cadmium (0.78; 95% CI 0.63-0.97) and male lead (0.85; 95% CI 0.73-0.98) concentrations. When jointly modeling couples' exposures, only male lead concentration significantly reduced the FOR (0.82; 95% CI 0.68, 0.97), though the FOR remained <1 for female cadmium (0.80; 95% CI 0.64, 1.00). This prospective couple based cohort with longitudinal capture of time to pregnancy is suggestive of cadmium and lead's reproductive toxicity at environmentally relevant concentrations.
Project description:To determine whether there is a significant association between prior cataract surgery and cognitive function in an elderly Japanese cohort.Nara Medical University, Nara, Japan.The Fujiwara-kyo Eye Study was a cross-sectional epidemiological study.The subjects were ? 68-years who lived in the Nara Prefecture and responded to recruitment notices. All of the subjects received comprehensive ophthalmological examinations, and answered questionnaires on their socio-demographic and medical history including prior cataract surgery. The association between prior cataract surgery and cognitive function was determined.A total of the 2764 subjects whose mean age was 76.3±4.8 years (±standard deviation) was studied. Of these, 668 individuals (24.2%) had undergone cataract surgery. Of these, 150 (5.4%) had dementia as determined by the Mini-Mental State Examination (MMSE) score ?23, and 877 individuals (31.7%) had mild cognitive impairment (MCI; MMSE score 24-26). The subjects who had prior cataract surgery had significantly lower odds ratio (OR) of having MCI (OR = 0.78, 95% confidence interval; CI 0.64-0.96, P = 0.019) than those who had not had cataract surgery after adjusting for age, sex, body mass index, education, hypertension, diabetes, depression, and history of stroke. The OR was still lower when the visual acuity was also added to the adjusted factors (OR 0.79, 95% CI 0.64-0.97, P = 0.025). However, prior cataract surgery did not contribute significantly to the low OR for dementia.Cataract surgery may play a role in reducing the risk of developing MCI independently of visual acuity but not for dementia.
Project description:Environmental cadmium and lead exposures are widespread, and both metals are nephrotoxic at high exposure levels. Few studies have evaluated the associations between low-level cadmium and clinical renal outcomes, particularly with respect to joint cadmium and lead exposure. The geometric mean levels of blood cadmium and lead were 0.41 microg/L (3.65 nmol/L) and 1.58 microg/dL (0.076 micromol/L), respectively, in 14,778 adults aged >or=20 years who participated in the National Health and Nutrition Examination Survey (1999-2006). After adjustment for survey year, sociodemographic factors, chronic kidney disease risk factors, and blood lead, the odds ratios for albuminuria (>or=30 mg/g creatinine), reduced estimated glomerular filtration rate (eGFR) (<60 mL/minute/1.73 m(2)), and both albuminuria and reduced eGFR were 1.92 (95% confidence interval (CI): 1.53, 2.43), 1.32 (95% CI: 1.04, 1.68), and 2.91 (95% CI: 1.76, 4.81), respectively, comparing the highest with the lowest blood cadmium quartiles. The odds ratios comparing participants in the highest with the lowest quartiles of both cadmium and lead were 2.34 (95% CI: 1.72, 3.18) for albuminuria, 1.98 (95% CI: 1.27, 3.10) for reduced eGFR, and 4.10 (95% CI: 1.58, 10.65) for both outcomes. These findings support consideration of cadmium and lead as chronic kidney disease risk factors in the general population and provide novel evidence of risk with environmental exposure to both metals.
Project description:Importance:Cataracts are the most common cause of impaired vision worldwide and may increase a driver's risk of a serious traffic crash. The potential benefits of cataract surgery for reducing a patient's subsequent risk of traffic crash are uncertain. Objective:To conduct a comprehensive longitudinal analysis testing whether cataract surgery is associated with a reduction in serious traffic crashes where the patient was the driver. Design, Setting, and Participants:Population-based individual-patient self-matching exposure-crossover design in Ontario, Canada, between April 1, 2006, and March 31, 2016. Consecutive patients 65 years and older undergoing cataract surgery (n?=?559?546). Interventions:First eye cataract extraction surgery (most patients received second eye soon after). Main Outcomes and Measures:Emergency department visit for a traffic crash as a driver. Results:Of the 559?546 patients, mean (SD) age was 76 (6) years, 58% were women (n?=?326?065), and 86% lived in a city (n?=?481?847). A total of 4680 traffic crashes (2.36 per 1000 patient-years) accrued during the 3.5-year baseline interval and 1200 traffic crashes (2.14 per 1000 patient-years) during the 1-year subsequent interval, representing 0.22 fewer crashes per 1000 patient-years following cataract surgery (odds ratio [OR], 0.91; 95% CI, 0.84-0.97; P?=?.004). The relative reduction included patients with diverse characteristics. No significant reduction was observed in other outcomes, such as traffic crashes where the patient was a passenger (OR, 1.03; 95% CI, 0.96-1.12) or pedestrian (OR, 1.02; 95% CI, 0.88-1.17), nor in other unrelated serious medical emergencies. Patients with younger age (OR, 1.27; 95% CI, 1.13-1.14), male sex (OR, 1.64; 95% CI, 1.46-1.85), a history of crash (baseline OR, 2.79; 95% CI, 1.94-4.02; induction OR, 4.26; 95% CI, 2.01-9.03), more emergency visits (OR, 1.34; 95% CI, 1.19-1.52), and frequent outpatient physician visits (OR, 1.17; 95% CI, 1.01-1.36) had higher risk of subsequent traffic crashes (multivariable model). Conclusions and Relevance:This study suggests that cataract surgery is associated with a modest decrease in a patient's subsequent risk of a serious traffic crash as a driver, which has potential implications for mortality, morbidity, and costs to society.
Project description:Changes in lens may reflect the status of systemic health of human beings but the supporting evidences are not well summarized yet. We aimed to determine the relationship of age-related cataract, cataract surgery and long-term mortality by pooling the results of published population-based studies.We searched PubMed and Embase from their inception till March, 2014 for population-based studies reporting the associations of any subtypes of age-related cataract, cataract surgery with all-cause mortality. We pooled the effect estimates (hazards ratios [HRs]) under a random effects model.Totally, we identified 10 unique population-based studies including 39,659 individuals at baseline reporting the associations of any subtypes of cataract with all-cause mortality from 6 countries. The presence of any cataract including cataract surgery was significantly associated with a higher risk of death (pooled HR: 1.43, 95% CI, 1.21, 2.02; P<0.001; I(2) = 64.2%). In the meta-analysis of 9 study findings, adults with nuclear cataract were at higher risks of mortality (pooled HR: 1.55, 95% CI, 1.17, 2.05; P = 0.002; I(2) = 89.2%). In the meta-analysis of 8 study findings, cortical cataract was associated with higher risks of mortality (pooled HR: 1.26, 95% CI, 1.12, 1.42; P<0.001, I(2) = 29.7%). In the meta-analysis of 6 study findings, PSC cataract was associated with higher risks of mortality (pooled HR: 1.37, 95% CI, 1.04, 1.80; P = 0.03; I(2) = 67.3%). The association between cataract surgery and mortality was marginally non-significant by pooling 8 study findings (pooled HR: 1.27, 95% CI, 0.97, 1.66; P = 0.08; I(2)= 76.6%).All subtypes of age-related cataract were associated with an increased mortality with nuclear cataract having the strongest association among the 3 cataract subtypes. However, cataract surgery was not significantly related to mortality. These findings indicated that changes in lens may serve as markers for ageing and systemic health in general population.
Project description:Low-level cadmium exposure, resulting in, for example, urinary cadmium <2.0 ?g/g creatinine, is widespread; recent data suggest nephrotoxicity even at these low levels. Few studies have examined the impact of low-level cadmium exposure in workers who are occupationally exposed to other nephrotoxicants such as lead.We evaluated associations of urine cadmium, a measure of cumulative dose, with four glomerular filtration measures and N-acetyl-?-D-glucosaminidase (NAG) in lead workers. Recent and cumulative lead doses were assessed via blood and tibia lead, respectively.In 712 lead workers, mean (SD) blood and tibia lead values, urine cadmium values and estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease equation were 23.1 (14.1) ?g/dl, 26.6 (28.9) ?g Pb/g bone mineral, 1.15 (0.66) ?g/g creatinine and 97.4 (19.2) ml/min/1.73 m(2), respectively. After adjustment for age, sex, body mass index, urine creatinine, smoking, alcohol, education, annual income, diastolic blood pressure, current or former lead worker job status, new or returning study participant, and blood and tibia lead, higher ln-urine cadmium was associated with higher calculated creatinine clearance, eGFR (? = 8.7 ml/min/1.73 m(2); 95% CI 5.4 to 12.1) and ln-NAG but lower serum creatinine.Potential explanations for these results include a normal physiological response in which urine cadmium levels reflect renal filtration, the impact of adjustment for urine dilution with creatinine in models of kidney outcomes, and cadmium-related hyperfiltration.
Project description:BACKGROUND:Environmental factors contributing to diabetic kidney disease are incompletely understood. We investigated whether blood cadmium and lead concentrations were associated with the prevalence of diabetic kidney disease, and to what extent lifestyle-related exposures (diet and smoking) contribute to blood cadmium and lead concentrations. MATERIAL AND METHODS:In a cross-sectional analysis in 231 patients with type 2 diabetes included in the DIAbetes and LifEstyle Cohort Twente (DIALECT-1), blood cadmium and lead concentrations were determined using inductively coupled plasma mass spectrometry. The associations between diet (derived from food frequency questionnaire), smoking and cadmium and lead were determined using multivariate linear regression. The associations between cadmium and lead and diabetic kidney disease (albumin excretion >30 mg/24 h and/or creatinine clearance <60 mL/min/1.73 m2) were determined using multivariate logistic regression. RESULTS:Median blood concentrations were 2.94 nmol/L (interquartile range (IQR): 1.78-4.98 nmol/L) for cadmium and 0.07 µmol/L (IQR: 0.04-0.09 µmol/L) for lead, i.e., below acute toxicity values. Every doubling of lead concentration was associated with a 1.75 (95% confidence interval (CI): 1.11-2.74) times higher risk for albuminuria. In addition, both cadmium (odds ratio (OR) 1.50 95% CI: 1.02-2.21) and lead (OR 1.83 95% CI: 1.07-3.15) were associated with an increased risk for reduced creatinine clearance. Both passive smoking and active smoking were positively associated with cadmium concentration. Alcohol intake was positively associated with lead concentration. No positive associations were found between dietary intake and cadmium or lead. CONCLUSIONS:The association between cadmium and lead and the prevalence of diabetic kidney disease suggests cadmium and lead might contribute to the development of diabetic kidney disease. Exposure to cadmium and lead could be a so far underappreciated nephrotoxic mechanism of smoking and alcohol consumption.
Project description:Although cadmium and lead are known risk factors for hearing loss in animal models, few epidemiologic studies have been conducted on their associations with hearing ability in the general population.We investigated the associations between blood cadmium and lead exposure and hearing loss in the U.S. general population while controlling for noise and other major risk factors contributing to hearing loss.We analyzed data from 3,698 U.S. adults 20-69 years of age who had been randomly assigned to the National Health and Nutrition Examination Survey (NHANES) 1999-2004 Audiometry Examination Component. Pure-tone averages (PTA) of hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz were computed, and hearing loss was defined as a PTA > 25 dB in either ear.The weighted geometric means of blood cadmium and lead were 0.40 [95% confidence interval (CI): 0.39. 0.42] µg/L and 1.54 (95% CI: 1.49, 1.60) µg/dL, respectively. After adjusting for sociodemographic and clinical risk factors and exposure to occupational and nonoccupational noise, the highest (vs. lowest) quintiles of cadmium and lead were associated with 13.8% (95% CI: 4.6%, 23.8%) and 18.6% (95% CI: 7.4%, 31.1%) increases in PTA, respectively (p-trends < 0.05).Our results suggest that low-level exposure to cadmium and lead found in the general U.S. population may be important risk factors for hearing loss. The findings support efforts to reduce environmental cadmium and lead exposures.