Diabetes Care, Vol 19, Issue 8 873-875, Copyright © 1996 by American Diabetes Association
Evidence of a relationship between childhood-onset type I diabetes and low groundwater concentration of zinc
B Haglund, K Ryckenberg, O Selinus and G Dahlquist
Centre for Epidemiology, National Board of Social Welfare, Stockholm, Sweden.
OBJECTIVE: Zinc deficiency has shown to increase the risk for diabetes in
diabetes-prone experimental animals. Low concentrations of zinc have also
been shown in serum of recent onset cases with IDDM. The present study
examines the hypothesis that exposure to a low concentration of zinc in
drinking water could increase the risk for future onset of IDDM. RESEARCH
DESIGN AND METHODS: Using the Swedish childhood diabetes registry and data
on residence 3 years before the onset of disease, a case-control study was
designed comparing cases and control subjects with estimates of groundwater
contents of zinc obtained in biogeochemical samples from areas of
residence. RESULTS: A high groundwater concentration of zinc was associated
with a significant decrease in risk (odds ration [OR] = 0.8; 95% CI =
0.7-0.9). The same OR was obtained when the model included information of
other metals that might act as possible confounders (chromium, vanadium,
cobalt selenium, cadmium, lead, and mercury). In small rural areas, in
which drinking water is taken from local wells and thus is closely
associated with the groundwater content within the area, an even stronger
association between zinc and diabetes (OR = 0.6; 95% CI = 0.4-0.9) was
found. CONCLUSIONS: It is concluded that this study for the first time
provides evidence that a low groundwater content of zinc, which may reflect
long-term exposure through drinking water, is associated with later
development of childhood onset diabetes.