School
School of Public Health
Document Type
Dissertation
Department (new version)
Public Health
Date of Award
1990
Degree Name by School
Doctor of Public Health (DrPH) School of Public Health
Abstract
In the eastern part of Shanxi, China, the mortality rates for esophageal cancer (EC) ranged from 8 to 113 per 100,000 person-years. This study explored the relationship between the unusually variable mortality rates and the dietary factors presented in the affected populations. Concentrations of eight trace elements (Zn, Cu, Fe, Cd, Ni, Mo, Se, Si) were measured in ten kinds of foods. Daily intakes of these trace elements were estimated based on actual measurements and on the food allocation account records for 1966. Calcium levels in some foods were also measured. The estimated daily intake of zinc were found to be inversely related to the esophageal cancer mortality rate; furthermore, the effects of dietary zinc deficiency were found to be strongly modified by the calcium level in these diets. When dietary calcium intake was low, the relative risk for esophageal cancer was 1.9 (95% CI: 1.0-3.5) for persons with a daily dietary zinc intake of less than 10.5 mg compared to those with intakes above that level. However, when calcium consumption was high, the relative risk for the low-zinc group increased to 6.2 (95% CI: 2.3-17.2). The consumption of corn and wheat flour was found to be positively related to the mortality rate from esophageal cancer (p = 0.0000). The increased risk associated with dietary zinc deficiency provides new epidemiological evidence to support the hypothesis that zinc deficiency is involved in the etiology of esophageal cancer, as has been suggested by previous immunological studies and animal experiments. This study also provides evidence of a new hypothesis that a link exists between calcium intake and the effect of zinc deficiency on esophageal cancer rates. Phytate and calcium were previously found to decrease zinc absorption rates through the formation of zinc-calcium-phytate complex. The apparent effect of high levels of calcium consumption on the risk of esophageal cancer can thus possibly be explained as a reflection of a decreased absorption rate for zinc. The effects of high levels of corn and wheat flour consumption on esophageal cancer mortality rates can be explained by the high levels of phytate that other researchers have reported to occur in these foods.
ProQuest Publication Number
ProQuest ID
9107143
ISBN
979-8-207-46364-3
Recommended Citation
Chen, Fan, "The effects of dietary zinc on esophageal cancer mortality rates in Shanxi, China" (1990). All ETDs from UAB. 7167.
https://digitalcommons.library.uab.edu/etd-collection/7167
Comments
DrPH