title: Dietary cadmium exposure and kidney stone incidence: a population-based prospective cohort study of men & women.
abstract: Cadmium exposure is associated with increased urinary calcium excretion. Hypercalciuria is recognised as a major risk factor for kidney stone formation. Increased prevalence of kidney stones among those occupationally exposed to cadmium has previously been suggested. Food is the main source of cadmium exposure in the general population with tobacco representing an important additional source among smokers. We aimed to assess the association between dietary cadmium exposure and kidney stone incidence in two large population-based, prospective cohorts of men (Cohort of Swedish Men; COSM) and women (The Swedish Mammography Cohort; SMC). Those with a history of kidney stones were excluded. At baseline 1997, men (45-79yrs) and women (48 to 83yrs), completed a self-administered questionnaire on diet and lifestyle. During 12years of follow-up, we ascertained 707 cases of kidney stones in men and 290 in women through linkage of the cohorts to the national inpatient and outpatient registers. Individual dietary cadmium exposure was estimated using dietary data and concentrations of cadmium in food. Hazard ratios (HR) were calculated using the Cox proportional hazards regression models with adjustment for other risk factors. Estimated dietary cadmium exposure was not associated with increased kidney stone incidence among men HR 0.97 (95% confidence interval (CI): 0.77-1.23) or women HR 0.99 (95% CI: 0.89-1.43), comparing the highest tertile with the lowest. In conclusion, our results do not support a strong association between dietary cadmium and kidney stone risk at the exposure levels seen in the general population.
authors.affiliation: Institute of Environmental Medicine, Unit of Nutritional Epidemiology, Karolinska Institutet, Box 210, 171 77 Stockholm, Sweden.
authors.forename: Laura D K
authors.initials: LD
authors.lastname: Thomas
authors.forename: Carl-Gustaf
authors.initials: CG
authors.lastname: Elinder
authors.forename: Hans-Göran
authors.initials: HG
authors.lastname: Tiselius
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
authors.forename: Agneta
authors.initials: A
authors.lastname: Akesson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002104:Cadmium / Q000009:adverse effects*; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects*; D005260:Female; D006801:Humans; D015994:Incidence; D007669:Kidney Calculi / Q000139:chemically induced / Q000453:epidemiology*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
chemical_list: D002104:Cadmium
keywords: BMI; CI; Cadmium; Diet; FFQ; HR; Kidney stones; OR; Prospective cohort; SD; TWI; body mass index; confidence interval; food frequency questionnaire; hazard ratio; odds ratio; standard deviations; tolerable weekly intake