Height, weight, menstrual and reproductive factors and risk of gastric cancer among Japanese postmenopausal women: Analysis by subsite and histologic subtype

Abstract

To clarify whether reproductive factors have an impact on gastric cancer in Japanese females, a case-control study was conducted using data from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), Japan. The study subjects included 365 postmenopausal women with gastric cancer and 1,825 age-class frequencymatched noncancer outpatients presenting at Aichi Cancer Center in 1988 -1998. Cases were further divided with regard to the anatomic subsite (upper third, middle third, lower third) and histologic subtypes (differentiated, nondifferentiated) and the association was evaluated using odds ratios Despite a decreasing trend, gastric cancer remains a major public health problem in Japan. The latest estimate shows that 22% of Japanese cancers occurred in the stomach in 1996, 1 and gastric cancers accounted for 18% of total cancer deaths in 1998. 2 It is well known that gastric cancer as a whole is more common in males, the male to female ratio being 1.5-3 in the incidence, 3 although this varies with the age group, 4 -6 values only being greater than 1 in middle-and old-aged groups. These observations suggest that the etiology of female gastric cancer may be different between the young and the old and therefore they should be considered separately.A previous study on gastric cancer in young individuals indicated an elevated risk of gastric cancer with pregnancy and delivery episode 7 and suggested that the sex hormones can influence the development of this cancer. 8 -10 On the other hand, the male predominance of this cancer in older age groups allows us to speculate some link not only with lifestyle factors such as smoking and dietary habits but also with a protective function of femalerelated factors. Our working hypothesis for our study was that whereas a male predominant lifestyle, including smoking, may increase the risk, long term exposure to female-related factors over a long fertile life may reduce the likelihood of gastric cancer. To our knowledge, epidemiologic studies targeting this issue hitherto have only been conducted in Western countries 11-21 and the results were not consistent, suggesting the need for separate analysis by subsite and histologic subtype. 17 To gain further epidemiologic evidence on any association between gastric cancer and female-related factors such as menstrual and reproductive factors among postmenopausal women, a comparative case-control study was therefore undertaken using data from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC). This study aimed to clarify whether these factors exhibit any impact on development of different types of gastric cancers in postmenopausal Japanese women. MATERIAL AND METHODSHERPACC was begun in Nagoya, Japan, in 1988, with information on lifestyle factors routinely collected from all first-visit outpatients, using a self-administered questionnaire checked by a trained interviewer. Each patient was asked about his or her lifestyle when healthy or before the current symptoms developed...

Does breastfeeding affect the risk of gastric cancer?

“…More detailed studies are clearly called for. It is still noteworthy that Inoue et al 1 found a similar inverse U-shaped relation with age at menopause as seen in our data 3 and in a previous study. 6 An inverse relation with age at first delivery for cancers of the distal stomach was also indicated in both data sets.…”

“…The Norwegian classification into subsites differs somewhat from that used in the Japanese data of Inoue et al, 1 in particular for the large group that represents an unknown subsite. It is unlikely, however, that imprecise subsite classification is related to the potential risk factors considered.…”

“…2,3 To our knowledge, there are no other reports on this relation except the recent one by Inoue et al 1 Prompted by the results in the Japanese study, we have now reanalysed our data in more detail on the basis of an extended follow-up.…”

Tamoxifen exposure and risk of oesophageal and gastric adenocarcinoma: a population-based cohort study of breast cancer patients in Sweden

“…A longer fertility period might reduce the gastric cancer risk (La Vecchia et al, 1994;Palli et al, 1994;Kaneko et al, 2003) and multiparity has been linked with a decreased risk (Kaneko et al, 2003). These results have been contradicted, however (Plesko et al, 1985;La Vecchia et al, 1994;Heuch and Kvale, 2000;Inoue et al, 2002). There are some previous results that suggest an increased risk of gastric adenocarcinoma among tamoxifen-treated patients.…”

Body Mass and Physical Activity and Risk of Gastric Cancer in a Population-Based Cohort Study in Norway

“…Although BMI is linked with an overall increase in the risk of cancer in general, results from casecontrol studies have indicated, rather, that a low BMI is associated with an increased risk of gastric cancer (7,8,(29)(30)(31), whereas results from prospective studies have yielded contradictory results (3,6,(9)(10)(11)(12)(13)(14)32). The lack of association between overweight or obesity and the risk of noncardia gastric cancer found in our study is in sharp contrast to the strong link that has been established between BMI and gastric cardia and esophageal adenocarcinoma (4-6).…”