Shanghai Women's Health Study: Cancer Risk Reduction and Diet - A Cohort Study of Women
Wei Zheng, M.D., Ph.D., M.P.H.
Vanderbilt University Medical Center
Department of Medicine
Nashville, Tenn.
Funded since 1996
Nutritional factors are thought to play a role in the etiology of over
one-third of all human cancers, yet information about the preventive potential
of specific dietary compounds is scanty. The Shanghai Women's Health Study
(SWHS) offers unique opportunities to fill such knowledge gaps.
The large-scale population-based cohort study includes 75,049 Chinese
women who were between ages 40 to 70 years at enrollment during 1997 to
2000 and lived in urban Shanghai, where intake levels of many hypothesized
cancer-inhibitory dietary factors are high and diverse. Detailed information
on dietary and other lifestyle factors was collected at baseline and again
in a follow-up survey. Biological samples were collected from the 87.5%
of cohort members. The cohort has been followed for cancer occurrence
and deaths through linkage with the population-based Shanghai Cancer Registry
and the Shanghai Vital Statistics Unit, and biannual visits to all living
cohort members.
This grant extends follow-up of the cohort and is to evaluate hypotheses
related to the etiology of cancers of the breast, colorectum, lung, and
stomach. The primary focus of the research is to determine whether certain
diets are associated with a reduced risk of cancer. Specifically diets
that include high intakes of:
- folate,
- soy foods,
- allium vegetables,
- crucifers, and
- regular tea drinking.
The investigators also are conducting nested case-control studies of
breast, lung, and colorectal cancers to evaluate whether the levels of
blood folate and urinary isothiocyanate and phytoestrogens are inversely
associated with the risk of these cancers. These biomarkers are aggregate
measures of the level of intake, absorption, and metabolism, and will
provide added insight in elucidating the relations of dietary factors
with cancer risk. The investigators will further evaluate in the nested
case-control studies whether the effect of dietary crucifer intake and
urinary isothiocyanate excretion may be modified by genotypes of the GST-family
genes.
Finally, the investigators will resurvey all living cohort members to
obtain updated information on usual dietary intake, physical activity,
and other lifestyle factors. This will enable them to refine exposure
assessment and to characterize and evaluate how temporal changes in exposures
may influence cancer risk.
Because of it size, setting, and inventory of baseline information and
biological specimens, the SWHS provides an exceptional opportunity to
address dietary hypotheses for cancer that cannot be adequately investigated
in any other existing cohort studies. The results from this study may
guide new strategies in the primary prevention of common cancer in both
Western and Asian women.
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