Chongqi Jia

Effects of physical activity, body mass index, waist-to-hip ratio and waist circumference on total mortality risk in the Swedish National March Cohort

The health benefits of physical activity (PA) have been well documented. However, there is less research investigating whether or not these health benefits might differ among males and females or among subjects characterized by different levels of body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC). Baseline total PA, BMI, WHR and waist circumference were measured in 14,585 men and 26,144 women who participated in the Swedish National March. Their effects on all-cause mortality were analyzed with a follow-up time of almost 10xa0years. Sedentary men with a BMIxa0≥xa030 had a 98% (95% CI: 30–201%) increased risk of mortality compared to normal weight men with a high level of total PA. The same trend was observed for sedentary men with high WHR or waist circumference, compared to lean and highly active men. Sedentary women with a waist circumference of 88xa0cm or more had almost doubled, i.e. 97% (95% CI: 35–189%) increased mortality risk compared to physically active women with a waist circumference below 80xa0cm. BMI in men, but waist circumference in women better forecast all-cause mortality. We found no substantial effect modification between different measures of adiposity and physical activity—physical inactivity and obesity seem to increase total mortality risk independently and additively.

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

There is a relation between excess body mass index and overall cancer incidence and mortality, but the relation to noncardia gastric cancer is inconsistent. A high physical activity level decreases the risk of several cancers, but few studies have focused on gastric cancer. We conducted a population-based, prospective cohort study in Nord-Trondelag county in Norway. During 1984 to 1986, all adult residents were invited to participate in a health survey, where body height and weight were measured, and frequency, duration, and intensity of recreational physical activity, together with potential confounding factors, were assessed by questionnaires. New gastric cancers occurring during follow-up in 1984 to 2002 were identified by linkage to the Cancer Registry of Norway. Cox proportional hazards regression models were used to calculate hazard ratios with 95% confidence intervals, adjusted for age, sex, occupation, salt intake, smoking, and alcohol drinking. Follow-up of 73,133 cohort members (88% of all inhabitants) revealed 313 gastric cancers, including 264 noncardia cancers. No statistically significant associations were revealed between different levels of body mass index and risk of noncardia gastric cancer. A statistically significant 50% risk reduction among persons reporting at least a moderate level of recreational physical activity, based on a summary score of physical activity (hazard ratio, 0.5; 95% confidence interval, 0.3-0.9), and a dose-response relation was indicated (P for trend = 0.01). It is concluded that recreational physical activity might have a protective effect against gastric cancer. The sedentary lifestyle gaining ground in western societies might counteract the ongoing decrease in incidence of gastric cancer. (Cancer Epidemiol Biomarkers Prev 2008;17(1):135–40)

Risk factors for malnutrition after oesophageal and cardia cancer surgery

Oesophageal cancer surgery is often followed by malnutrition, but the factors causing weight loss are unknown. The aim of this population‐based study was to identify such risk factors.

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

In a population-based cohort study of all women aged over 50 years with breast cancer in the Swedish Cancer Register in 1961–2003, those diagnosed before 31 December 1987 were regarded as unexposed to tamoxifen, whereas those diagnosed after that date were considered potentially exposed. Crosslinkages within the Cancer Register and the Registers of Death and Emigration enabled follow-up. Standardised incidence ratios (SIRs) of oesophageal and gastric cancer represented relative risks. Among 138u2009885 cohort members contributing with 1u2009075u2009724 person-years of follow-up, we found a nonsignificantly increased risk of oesophageal adenocarcinoma during the potential tamoxifen exposure period (SIR 1.60, 95% confidence interval (CI) 0.83–3.08), but the risk estimates decreased with increasing latency interval. No association was observed during the unexposed period. No increased risk of cardia adenocarcinoma was identified in either period. The risk of non-cardia gastric adenocarcinoma was increased in the potential tamoxifen period (SIR 1.27, 1.03–1.57), and almost doubled (SIR 1.86, 95% CI 1.10–3.14) in the period of longest latency (10–14 years). The corresponding overall SIR was increased in the unexposed group also, but here SIR did not increase with longer latency intervals. An increased risk of tobacco-related tumours, that is, oesophageal squamous-cell carcinoma and lung cancer, was limited to the unexposed cohort, indicating that confounding by smoking might explain the increased SIR during the unexposed period. We concluded that there might be a link between tamoxifen and risk of non-cardia gastric adenocarcinoma.

Endogenous estrogen exposure in relation to distribution of histological type and estrogen receptors in gastric adenocarcinoma

BackgroundEstrogen might protect women against gastric adenocarcinoma of the intestinal histological type. We addressed this hypothesis and proposed that gastric estrogen receptors (ERs) are involved.MethodsA population-based cohort of patients with gastric adenocarcinoma diagnosed in 1958–2004 in the county of Stockholm was identified through the Swedish Cancer Register. The patients were categorized regarding their endogenous estrogen exposure at diagnosis into: women aged less than 50 years, labelled “exposed women” (n = 364), men aged less than 50 years, labelled “unexposed men” (n = 396), and women aged more than 70 years, labelled “unexposed women” (n = 3008). Tumor specimens were reviewed, and 289 cases were classified into intestinal (n = 101) or diffuse type (n = 188). Cases of intestinal adenocarcinomas (n = 45) were tested for presence of ERalpha, ERbeta, and ERbeta cx by immunohistochemistry.ResultsCompared to “exposed women”, the intestinal type of gastric adenocarcinoma was more than four times more common among “unexposed men” (odds ratio [OR], 4.7; 95% confidence interval [CI], 2.2–10.3) and nine times more common among “unexposed women” (OR, 9.1; 95% CI, 4.3–19.6). No differences in ER expression were found. A comparison of ERs in tissues taken from the tumors and adjacent gastric mucosa revealed a loss of ERbeta and a gain of ERalpha in the tumor cells. The presence of ERbeta cx was identified for the first time in gastric tumors.ConclusionGastric adenocarcinoma of the intestinal type is less common in women with high endogenous estrogen exposure, indicating a preventive effect of estrogen. No differences in the distribution of ERs was found between the three estrogen exposure groups. The presence of ERbeta cx in gastric cancer warrants further investigation.

Tamoxifen exposure in relation to gastric adenocarcinoma development

Epidemiological research has indicated that the anti-oestrogen tamoxifen, used in breast cancer therapy, may increase the risk of gastric adenocarcinoma of the intestinal but not of the diffuse type. To test this hypothesis, and evaluate possible involvement of oestrogen receptors (ERs), we conducted a study amongst tamoxifen users and non-users. The study participants comprised women in the county of Stockholm who in the Swedish Cancer Register were first recorded with breast cancer and subsequently gastric cancer during the period January 1958-August 2005. Medical records were scrutinised to verify the diagnoses and classify into use or non-use of tamoxifen. Tumour material was reviewed histologically to verify gastric adenocarcinoma diagnosis and classify these cancers into intestinal or diffuse type. Intestinal adenocarcinomas were analysed immunohistochemically for the presence of ER alpha, beta and beta cx. Amongst 68 women with verified gastric adenocarcinoma, 30 had been treated with tamoxifen and 38 not. The intestinal type of gastric adenocarcinoma was not more frequent amongst tamoxifen users (27%) than amongst non-users (34%) (p=0.601). There were no material differences between the tamoxifen groups regarding distribution of any of the three ERs of the intestinal adenocarcinoma specimens. Tamoxifen users had a shorter latency between breast cancer and gastric adenocarcinoma (4 versus 13 years) which was similar in the intestinal and diffuse types. This study does not support the hypothesis that tamoxifen increases the isolated risk of the intestinal type, but it indicates that tamoxifen use might accelerate the tumour progression or increase the overall risk of gastric adenocarcinoma.

Influence of maternal parity, age, and ethnicity on risk of esophageal atresia in the infant in a population-based study

BACKGROUNDnThe etiology of esophageal atresia (EA) is virtually unknown. We hypothesized that the maternal factors low parity, high age, and white ethnicity are involved.nnnMETHODSnA Swedish nationwide, population-based, case-control study was nested in a cohort of newborn children in 1982 to 2004. Among 2,305,858 deliveries, 722 cases of EA and 3610 controls were included. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Matching, stratification, and multivariable regression were used to adjust for potential confounding.nnnRESULTSnA more than 30% decreased risk of EA was found for mothers delivering their second (OR, 0.68; 95% CI, 0.56-0.83) or third child (OR, 0.64; 95% CI, 0.49-0.83) compared to primiparous mothers. Children of women giving birth when 35 to 40 years and older than 40 years showed a 2-fold (OR, 2.09; 95% CI, 1.09-3.99) and 3-fold (OR, 3.04; 95% CI, 1.37-6.74) increased risk of EA, respectively, compared to those of mothers younger than 20 years. This association remained when chromosomal abnormality cases were excluded (P = .004). There was a 66% increase in risk of isolated EA in children of mothers of white (OR, 1.66; 95% CI, 1.06-2.61), compared to mothers who are not of white ethnicity.nnnCONCLUSIONSnThis study indicates an increased risk of EA in children of mothers having their first delivery, of older age, and of white ethnicity.

Maternal tobacco smoking, obesity, and low socioeconomic status during early pregnancy in the etiology of esophageal atresia

BACKGROUNDnThe etiology of the congenital malformation esophageal atresia (EA) is essentially unknown. We hypothesized that maternal tobacco smoking, obesity, and low socioeconomic status (SES) during early pregnancy might increase the risk of the fetus developing EA.nnnMETHODSnA nationwide, population-based, case-control study was nested in a cohort of children born in Sweden in 1982 to 2004. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using logistic regression. Matching, stratification, and multivariable regression were used to control for confounding.nnnRESULTSnAmong 2,305,858 newborn children constituting the study cohort, 722 cases of EA and 3610 controls were included. For women smoking 10 cigarettes or more daily, the adjusted OR was 0.88 (95% CI, 0.62-1.25) compared to nonsmokers. For obese women (body mass index, >30), OR was 0.99 (95% CI, 0.64-1.55) compared to lean women (body mass index, <20). Women with more than 12 years of formal education, representing SES, had an OR of 0.94 (95% CI, 0.69-1.29) compared to those with less than 10 years of education. The lack of association remained in stratified analyses of isolated EA and EA accompanied by associated malformations.nnnCONCLUSIONnThis study provides evidence refuting the hypotheses of an increased risk of EA among children of women who smoke, are obese, or have a low SES during early pregnancy.

Salt and Gastric Adenocarcinoma: A Population-Based Cohort Study in Norway

Background: Gastric adenocarcinoma is the second leading cause of cancer death worldwide. It has been suggested that consumption of salted foods is associated with increased risk of this cancer, but the results of the few available prospective studies are contradictory. Methods: A population-based, prospective cohort study in Nord-Trondelag County in Norway during 1984 to 2002 addressed dietary salt intake in relation to risk of gastric adenocarcinoma. In 1984 to 1986, all adult county residents were invited to a health survey in which participants answered questionnaires concerning dietary salt intake and other factors. Gastric adenocarcinomas were identified in the Norwegian Cancer Registry. Relative risks were calculated using Cox proportional hazards regression models, adjusted for potentially confounding factors. Results: Follow-up of 1,122,765 person-years at risk among 73,133 cohort members disclosed 313 incident cases of gastric adenocarcinomas occurring at least 3 years after inclusion into the cohort. There were no statistically significant associations between different levels of salt intake and risk of gastric adenocarcinoma. High consumers of dietary salt were not at increased risk of developing gastric adenocarcinoma compared with low consumers (hazard ratio, 1.0; 95% confidence interval, 0.7-1.4), and no dose-response effect was observed (Ptrend = 0.55). Conclusion: High intake of dietary salt does not appear to increase the risk of gastric adenocarcinoma in this low-incidence western population. (Cancer Epidemiol Biomarkers Prev 2008;17(8):1997–2001)