Follow-up on a 1962 case-control study of trace elements as risk factors for stomach cancer in Iceland

Abstract

In 1988 a follow-up investigation was made of a case-control study conducted in 1962 in Iceland which tested hypotheses that trace elements in pasture grass, drinking water and cow's milk were associated through diet with cancer of the stomach. Samples were collected in 1962 from 26 farms in the northern county of Skagafjardarsysla and 30 farms in the southern county of Rangarvallasysla. The main objective of the present study was to establish the cancer experience of the 297 residents of the 56 farms since 1962. In the records of the Icelandic Cancer Registry 31 cases of cancer of all types were identified. Six were cancers of the stomach and four of these were from control farms. The revised comparison of trace element analyses for case and control farms yielded no change in earlier results for pasture grass in Skagafjardarsysla (excess levels of B, Na, AI, Fe and Cu on cancer farms), but B appeared as a significant deficiency on cancer farms in Rangarvallasysla. Drinking water results were unchanged (no significant differences), but for milk the significantly high mean values of Fe and Zn reported earlier for Rangarvallasysla did not appear. The pronounced geographical variation in Icelandic stomach cancer incidence that was widely cited from 1961-65 is now believed to have been spurious.

The Nutritional Importance and Pharmacological Potential of Boron for Higher Animals and Human

“…In the county of Rangarvallasysla in Iceland, boron deficiency in pasture grass, drinking water and cow's milk was associated with cancer of the stomach (Armstrong, 1990). Based on a study of 76 cases and 7751 controls, low dietary boron intake was associated with increased prostrate cancer risk (Zhang et aI., 2001).…”

Trace elements in the human environment: Problems and risks

“…For example, Piispanen (1989) compared cancer and geochemical maps of Finland but found only weak associations. When Armstrong (1990) revisited an earlier study area in Iceland he concluded that the pronounced geographical variation in Icelandic stomach cancer incidence that was widely cited from 1961 to 1965 is now believed to be spurious. Multiple sclerosis is a relatively uncommon disease which is very difficult to diagnose in its early stages.…”