Cadmium exposure and incidence of diabetes mellitus--results from the Malmö Diet and Cancer study.
BACKGROUND
Cadmium is a pollutant with multiple adverse health effects: renal dysfunction, osteoporosis and fractures, cancer, and probably cardiovascular disease. Some studies have reported associations between cadmium and impaired fasting glucose and diabetes. However, this relationship is controversial and there is a lack of longitudinal studies.


OBJECTIVE
To examine prospectively whether cadmium in blood is associated with incidence of diabetes mellitus.


METHODS
The study population consists of 4585 subjects without history of diabetes (aged 46 to 67 years, 60% women), who participated in the Malmö Diet and Cancer study during 1991-1994. Blood cadmium levels were estimated from hematocrit and cadmium concentrations in erythrocytes. Incident cases of diabetes were identified from national and local diabetes registers.


RESULTS
Cadmium concentrations in blood were not associated with blood glucose and insulin levels at the baseline examination. However, cadmium was positively associated with HbA1c in former smokers and current smokers. During a mean follow-up of 15.2 ± 4.2 years, 622 (299 men and 323 women) were diagnosed with new-onset of diabetes. The incidence of diabetes was not significantly associated with blood cadmium level at baseline, neither in men or women. The hazard ratio (4th vs 1st quartile) was 1.11 (95% confidence interval 0.82-1.49), when adjusted for potential confounders.


CONCLUSIONS
Elevated blood cadmium levels are not associated with increased incidence of diabetes. The positive association between HbA1c and blood cadmium levels has a likely explanation in mechanisms related to erythrocyte turnover and smoking.
Department of Clinical Sciences in Malmö, Lund University, Skåne University Hospital, Malmö, Sweden.
Yan
Y
Borné
Sahlgrenska Center for Cardiovascular and Metabolic Research, Wallenberg Laboratory, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden.
Björn
B
Fagerberg
Department of Clinical Sciences in Malmö, Lund University, Skåne University Hospital, Malmö, Sweden; Clinical Research Unit, Emergency Department, Skåne University Hospital, Malmö, Sweden.
Margaretha
M
Persson
Occupational and Environmental Medicine, Sahlgrenska University Hospital and University of Gothenburg, Gothenburg, Sweden.
Gerd
G
Sallsten
Department of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden.
Niklas
N
Forsgard
Department of Clinical Sciences in Malmö, Lund University, Skåne University Hospital, Malmö, Sweden.
Bo
B
Hedblad
Occupational and Environmental Medicine, Sahlgrenska University Hospital and University of Gothenburg, Gothenburg, Sweden.
Lars
L
Barregard
Department of Clinical Sciences in Malmö, Lund University, Skåne University Hospital, Malmö, Sweden.
Gunnar
G
Engström
D000368:Aged; D002104:Cadmium / Q000097:blood*; D003920:Diabetes Mellitus / Q000453:epidemiology*; D004781:Environmental Exposure; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012907:Smoking
D002104:Cadmium; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human