Mortality and cancer in relation to ABO blood group phenotypes in the Golestan Cohort Study

BACKGROUND

A few studies have shown an association between blood group alleles and vascular disease, including atherosclerosis, which is thought to be due to the higher level of von Willebrand factor in these individuals and the association of blood group locus variants with plasma lipid levels. No large population-based study has explored this association with overall and cause-specific mortality.

METHODS

We aimed to study the association between ABO blood groups and overall and cause-specific mortality in the Golestan Cohort Study. In this cohort, 50,045 people 40- to 70-years old were recruited between 2004 and 2008, and followed annually to capture all incident cancers and deaths due to any cause. We used Cox regression models adjusted for age, sex, smoking, socioeconomic status, ethnicity, place of residence, education and opium use.

RESULTS

During a total of 346,708 person-years of follow-up (mean duration 6.9 years), 3,623 cohort participants died. Non-O blood groups were associated with significantly increased total mortality (hazard ratio (HR) = 1.09; 95% confidence interval (CI): 1.01 to 1.17) and cardiovascular disease mortality (HR = 1.15; 95% CI: 1.03 to 1.27). Blood group was not significantly associated with overall cancer mortality, but people with group A, group B, and all non-O blood groups combined had increased risk of incident gastric cancer. In a subgroup of cohort participants, we also showed higher plasma total cholesterol and low-density lipoprotein (LDL) in those with blood group A.

CONCLUSIONS

Non-O blood groups have an increased mortality, particularly due to cardiovascular diseases, which may be due to the effect of blood group alleles on blood biochemistry or their effect on von Willebrand factor and factor VIII levels.

Polycyclic aromatic hydrocarbons and risk of gastric cancer in the Shanghai Women's Health Study

PURPOSE

Polycyclic aromatic hydrocarbons (PAHs) are byproducts of incomplete combustion of organic materials. Sources include tobacco smoke, charbroiled meat, and air pollution. Indirect evidence suggests that PAHs may be associated with carcinogenesis, but the association with gastric cancer is unclear.

METHODS

Using a nested case-control study design, we examined prediagnostic urinary concentrations of 1-hydroxypyrene glucuronide (1-OHPG), a PAH metabolite, in 153 gastric cancer cases and 306 matched controls within the Shanghai Women's Health Study. Conditional logistic regression adjusted for potential risk factors was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Urinary 1-OHPG concentrations were slightly higher among cases than controls, with medians of 0.29 μmol/mol Cr (interquartile range, 0.16-0.48) and 0.24 μmol/mol Cr (interquartile range, 0.12-0.45), respectively. Increasing concentrations of 1-OHPG appeared to be associated with elevated risk of gastric cancer, but not within the highest category of 1-OHPG (Q4 vs Q1: OR = 1.4; 95% CI = 0.8-2.5).

CONCLUSIONS

Our findings suggest that higher concentrations of 1-OHPG are related to gastric cancer risk, but no clear dose-response relationship was observed.

Validity and reliability of a questionnaire designed to assess risk factors of pancreatic cancer in Iran

BACKGROUND

The objective of this study is to develop a questionnaire to study risk factors of pancreatic cancer in Iran and to assess its reliability and validity.

METHODS

Following a comprehensive literature search and consulting with six expert gastroenterologists,these domains were included in the questionnaire: demographic variables; anthropometric indices; socioeconomic status indicators; signs and symptoms of the current disease; occupational history and exposure to certain physical and chemical agents; medical and drug history; family history of cancer; history of alcohol, tobacco, or opium use; history of tea and coffee consumption; pregnancy and menstrual data (only for women); and dietary habits and cooking methods. A total of 113 questions were developed and included in the questionnaire. Content validity was assessed by six gastroenterologists, three lay experts, and one methodologist. Reliability was evaluated using test-retest. Ten case subjects and 15 control subjects completed the questionnaire twice with time intervals of two or three weeks.

RESULTS

Overall, the validity and reliability of the questionnaire were acceptable. Item content validity index for clarity was above the predetermined level of 0.80 or higher for 112 (out of 113) questions. The corresponding index for relevancy was 0.80 or higher for 111 (out of 113) questions. The overall scale validity index for clarity and relevancy were 0.97 and 0.96, respectively. Inter-rater agreement for clarity and relevancy were 0.81 and 0.83 respectively. The scale comprehensiveness score was 100%. Regarding reliability, the intraclass correlation coefficients and kappa statistics were above the predetermined level of 0.70, except for four items. For the small minority of items that did not meet the predetermined standards (0.80 for validity and 0.80 for reliability), modifications were made based on consensus.

CONCLUSION

The questionnaire can be used for research purposes in the relevant studies.

Predicting gangrenous cholecystitis

BACKGROUND

Gangrenous cholecystitis (GC) is often challenging to treat. The objectives of this study were to determine the accuracy of pre-operative diagnosis, to assess the rate of post-cholecystectomy complications and to assess models to predict GC.

METHODS

A retrospective single-institution review identified patients undergoing a cholecystectomy. Logistic regression models were used to examine the association of variables with GC and to build risk-assessment models.

RESULTS

Of 5812 patients undergoing a cholecystectomy, 2219 had acute, 4837 chronic and 351 GC. Surgeons diagnosed GC pre-operatively in only 9% of cases. Patients with GC had more complications, including bile-duct injury, increased estimated blood loss (EBL) and more frequent open cholecystectomies. In unadjusted analyses, variables significantly associated with GC included: age >45 years, male gender, heart rate (HR) >90, white blood cell count (WBC) >13,000/mm(3), gallbladder wall thickening (GBWT) ≥ 4 mm, pericholecystic fluid (PCCF) and American Society of Anesthesiology (ASA) >2. In adjusted analyses, age, WBC, GBWT and HR, but not gender, PCCF or ASA remained statistically significant. A 5-point scoring system was created: 0 points gave a 2% probability of GC and 5 points a 63% probability.

CONCLUSION

Using models can improve a diagnosis of GC pre-operatively. A prediction of GC pre-operatively may allow surgeons to be better prepared for a difficult operation.

Contact with ruminants is associated with esophageal squamous cell carcinoma risk

The etiology of esophageal squamous cell carcinoma (ESCC) in the high risk area of northern Iran is only partially known. We aimed to investigate prolonged animal contact as a risk factor for ESCC in this population. From 2003 to 2007, we administered a validated questionnaire to 300 ESCC cases and 571 randomly selected controls matched for neighborhood of residence, age (±2 years) and sex. Questions on lifelong exposure to equines, ruminants, canines, and poultry, including duration and level of contact, were asked in a face-to-face interviews. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) adjusted for potential confounders. A total of 94.7% of cases and 68.7% of controls reported lifelong history of contact with ruminants. After controlling for potential confounders, contact with ruminants was associated with an eightfold increase (95% CI: 3.92-14.86) in risk of ESCC, and increments in duration of contact raised the risk estimates in a dose-dependent manner. Contact with equines and poultry did not significantly change associated OR for ESCC risk and contact with ruminants. OR (95% CI) for contact with canines was 1.99 (1.35-2.93) which after exclusion of contact with ruminants was not significant (OR for contact only with canine: 3.18, 95% CI: 0.73-13.17). These results add to the evidence that contact with ruminants may increase the risk of ESCC.

Massive splenomegaly correlates with malignancy: 180 cases of splenic littoral cell tumors in the world literature

Littoral cell tumors (LCT) are rare primary splenic neoplasms, unique for their morphologic and immunolabeling features resembling the endothelial littoral cells lining the sinusoids of the red pulp. They include the more common and typically benign littoral cell angioma, as well as the less common, potentially malignant, littoral cell hemangioendothelioma (LCHE) and the aggressive littoral cell angiosarcoma (LCAS). The most common presentation of these neoplasms is splenomegaly, and diagnosis is made histologically following biopsy or resection. To better understand these tumors, a comprehensive, international literature search was performed. Patient and tumor data, including presenting symptoms, comorbid cancers, immunosuppressive states, splenic mass and tumor size were analyzed. Massive splenomegaly (≥ 1500 g) following splenic resection, which correlates with a splenic length of 20 cm preoperatively, was found to be significantly associated with the presence of malignancy in the LCT (P<0.05).

Gastroesophageal reflux in relation to adenocarcinomas of the esophagus: a pooled analysis from the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON)

BACKGROUND

Previous studies have evidenced an association between gastroesophageal reflux and esophageal adenocarcinoma (EA). It is unknown to what extent these associations vary by population, age, sex, body mass index, and cigarette smoking, or whether duration and frequency of symptoms interact in predicting risk. The Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) allowed an in-depth assessment of these issues.

METHODS

Detailed information on heartburn and regurgitation symptoms and covariates were available from five BEACON case-control studies of EA and esophagogastric junction adenocarcinoma (EGJA). We conducted single-study multivariable logistic regressions followed by random-effects meta-analysis. Stratified analyses, meta-regressions, and sensitivity analyses were also conducted.

RESULTS

Five studies provided 1,128 EA cases, 1,229 EGJA cases, and 4,057 controls for analysis. All summary estimates indicated positive, significant associations between heartburn/regurgitation symptoms and EA. Increasing heartburn duration was associated with increasing EA risk; odds ratios were 2.80, 3.85, and 6.24 for symptom durations of <10 years, 10 to <20 years, and ≥20 years. Associations with EGJA were slighter weaker, but still statistically significant for those with the highest exposure. Both frequency and duration of heartburn/regurgitation symptoms were independently associated with higher risk. We observed similar strengths of associations when stratified by age, sex, cigarette smoking, and body mass index.

CONCLUSIONS

This analysis indicates that the association between heartburn/regurgitation symptoms and EA is strong, increases with increased duration and/or frequency, and is consistent across major risk factors. Weaker associations for EGJA suggest that this cancer site has a dissimilar pathogenesis or represents a mixed population of patients.

Unilateral nevoid telangiectasia syndrome (UNTS) associated with chronic hepatitis C virus and positive immunoreactivity for VEGF

Unilateral Nevoid Telangectasia Syndrome (UNTS) is characterized by superficial telangiectasias in a unilateral distribution. Vascular endothelial growth factor (VEGF) may play a role in the pathogenesis of UNTS in patients with underlying hepatic disease. We report a case of a patient with UNTS accompanied by chronic hepatitis C virus infection, with a normal serum estrogen profile and strong positive immunohistochemical staining of lesional skin with VEGF.

Gastric cancer: descriptive epidemiology, risk factors, screening, and prevention

Less than a century ago, gastric cancer was the most common cancer in the United States and perhaps throughout the world. Despite its worldwide decline in incidence over the past century, gastric cancer remains a major killer across the globe. This article reviews the epidemiology, screening, and prevention of gastric cancer. We first discuss the descriptive epidemiology of gastric cancer, including its incidence, survival, mortality, and trends over time. Next, we characterize the risk factors for gastric cancer, both environmental and genetic. Serologic markers and histological precursor lesions of gastric cancer and early detection of gastric cancer using these markers are reviewed. Finally, we discuss prevention strategies and provide suggestions for further research.

Gastric cancer: descriptive epidemiology, risk factors, screening, and prevention

Less than a century ago, gastric cancer was the most common cancer in the United States and perhaps throughout the world. Despite its worldwide decline in incidence over the past century, gastric cancer remains a major killer across the globe. This article reviews the epidemiology, screening, and prevention of gastric cancer. We first discuss the descriptive epidemiology of gastric cancer, including its incidence, survival, mortality, and trends over time. Next, we characterize the risk factors for gastric cancer, both environmental and genetic. Serologic markers and histological precursor lesions of gastric cancer and early detection of gastric cancer using these markers are reviewed. Finally, we discuss prevention strategies and provide suggestions for further research.

Gastroesophageal Reflux Disease and overall and Cause-specific Mortality: A Prospective Study of 50000 Individuals

BACKGROUND Only a few studies in Western countries have investigated the association between gastroesophageal reflux disease (GERD) and mortality at the general population level and they have shown mixed results. This study investigated the association between GERD symptoms and overall and cause-specific mortality in a large prospective population-based study in Golestan Province, Iran. METHODS Baseline data on frequency, onset time, and patient-perceived severity of GERD symptoms were available for 50001 participants in the Golestan Cohort Study (GCS). We identified 3107 deaths (including 1146 circulatory and 470 cancer-related) with an average follow-up of 6.4 years and calculated hazard ratios (HR) and 95% confidence intervals (CI) adjusted for multiple potential confounders. RESULTS Severe daily symptoms (defined as symptoms interfering with daily work or causing nighttime awakenings on a daily bases, reported by 4.3% of participants) were associated with cancer mortality (HR 1.48, 95% CI: 1.04-2.05). This increase was too small to noticeably affect overall mortality. Mortality was not associated with onset time or frequency of GERD and was not increased with mild to moderate symptoms. CONCLUSION We have observed an association with GERD and increased cancer mortality in a small group of individuals that had severe symptoms. Most patients with mild to moderate GERD can be re-assured that their symptoms are not associated with increased mortality.

Gastric cancer: descriptive epidemiology, risk factors, screening, and prevention

Less than a century ago, gastric cancer was the most common cancer in the United States and perhaps throughout the world. Despite its worldwide decline in incidence over the past century, gastric cancer remains a major killer across the globe. This article reviews the epidemiology, screening, and prevention of gastric cancer. We first discuss the descriptive epidemiology of gastric cancer, including its incidence, survival, mortality, and trends over time. Next, we characterize the risk factors for gastric cancer, both environmental and genetic. Serologic markers and histological precursor lesions of gastric cancer and early detection of gastric cancer using these markers are reviewed. Finally, we discuss prevention strategies and provide suggestions for further research.

Impact of body size and physical activity during adolescence and adult life on overall and cause-specific mortality in a large cohort study from Iran

We conducted this study to examine life-course body size and physical activity in relation to total and cause-specific mortality, which has not previously been studied in the low and middle-income countries in Asia. The Golestan Cohort Study is a population-based cohort in northeastern Iran in which 50,045 people above the age of 40 have been followed since 2004. Participants were shown a validated pictogram to assess body size at ages 15, 30, and the time of recruitment. Information on occupational physical activity at these ages was also collected. Subjects were followed up annually, and cause of death was determined. Cox regression models were adjusted for age at cohort start, smoking, socioeconomic status, ethnicity, place of residence, education, and opium use. Models for body size were also adjusted for physical activity at the same age, and vice versa. During a total of 252,740 person-years of follow-up (mean follow-up duration 5.1 ± 1.3 years) through December 2011, 2,529 of the cohort participants died. Larger body sizes at ages 15 or 30 in both sexes were associated with increased overall mortality. Cancer mortality was more strongly associated with adolescent obesity, and cardiovascular mortality with early adulthood body size. Weight gain between these ages was associated with cardiovascular mortality. Obese adolescents who lost weight still had increased mortality from all medical causes in both sexes. Physical activity during adolescence and early adulthood had no association with mortality, but at cohort baseline higher levels of activity were associated with reduced mortality. Mortality in this Middle-Eastern population was associated with obesity both during adolescence and early adult life.

Determinants of gastroesophageal reflux disease, including hookah smoking and opium use- a cross-sectional analysis of 50,000 individuals

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common cause of discomfort and morbidity worldwide. However, information on determinants of GERD from large-scale studies in low- to medium-income countries is limited. We investigated the factors associated with different measures of GERD symptoms, including frequency, patient-perceived severity, and onset time.

METHODS

We performed a cross-sectional analysis of the baseline data from a population-based cohort study of ∼ 50,000 individuals in in Golestan Province, Iran. GERD symptoms in this study included regurgitation and/or heartburn.

RESULTS

Approximately 20% of participants reported at least weekly symptoms. Daily symptoms were less commonly reported by men, those of Turkmen ethnicity, and nass chewers. On the other hand, age, body mass index, alcohol drinking, cigarette smoking, opium use, lower socioeconomic status, and lower physical activity were associated with daily symptoms. Most of these factors showed similar associations with severe symptoms. Women with higher BMI and waist to hip ratio were more likely to report frequent and severe GERD symptoms. Hookah smoking (OR 1.34, 95% CI 1.02-1.75) and opium use (OR 1.70, 95% CI 1.55-1.87) were associated with severe symptoms, whereas nass chewing had an inverse association (OR 0.87, 95% CI 0.76-0.99). After exclusion of cigarette smokers, hookah smoking was still positively associated and nass chewing was inversely associated with GERD symptoms (all frequencies combined).

CONCLUSION

GERD is common in this population. The associations of hookah and opium use and inverse association of nass use with GERD symptoms are reported for the first time. Further studies are required to investigate the nature of these associations. Other determinants of GERD were mostly comparable to those reported elsewhere.

A U-shaped relationship between haematocrit and mortality in a large prospective cohort study

BACKGROUND

Only a limited number of studies have investigated the correlation between haematocrit (HCT) and mortality in the general population, and few of those studies have had data on a wide range of low and high levels of HCT. We investigated the association between baseline HCT and mortality in a prospective cohort study of 49,983 adult subjects in Iran with a broad spectrum of HCT values.

METHODS

Data on socio-demographic and life-style factors, past medical history, and levels of HCT were collected at enrollment. During a mean follow-up of 5 years (follow-up success rate ~99%), 2262 deaths were reported. Cox proportional hazards regression models were used to estimate hazard ratios and corresponding 95% confidence intervals.

RESULTS

There was a U-shaped relationship between categories of HCT and mortality in both sexes: both low and high levels of HCT were associated with increased overall mortality and mortality from cardiovascular disease. The U-shaped relationship persisted after several sensitivity analyses were done, including analyses restricted to non-smokers and non-users of opium; analyses excluding deaths from accidents and other external causes as well as deaths of persons with self-reported ischemic heart disease at the baseline interview for the study; and analyses excluding the first 2 years of follow-up. Self-reported past medical history and lack of data about lipids and other cellular blood components were the major limitations of the study.

CONCLUSIONS

Low and high levels of HCT are associated with increased mortality in the general population. The findings in the present study can be of particular importance for low- and middle-income countries in which a substantial proportion of the population lives with suboptimal levels of HCT.

Sample size calculation for epidemiologic studies: principles and methods

This paper discusses the statistical principles, methods, and software programs used to calculate sample size. In addition, it reviews the practical challenges faced in calculating sample size. We show that because of such challenges, statistical calculations often do not provide us with a clear-cut number for the study sample size; rather they suggest a range of reasonable numbers. The paper also discusses several important nonstatistical considerations in determination of sample size, such as novelty of the study and availability of resources.

The state of nutritional epidemiology: why we are still unsure of what we should eat?

Most people want to know how they can improve their health by implementation of a proper diet. Therefore nutritional epidemiology studies, which correlate the intake of specific nutrients, food items, or dietary patterns with health outcomes, receive substantial interest in the media. However, the results of many nutritional epidemiology studies have not been replicated in subsequent studies. This paper reviews the primary methodological problems in nutritional epidemiology that result in lack of replicability and inconsistency across studies. The problematic methodological issues include substantial measurement error, confounding, the variable effects of food items, variable reference groups, interactions, and multiple testing.

Cooking methods and esophageal squamous cell carcinoma in high-risk areas of Iran

Cooking methods have been implicated in the etiology of gastrointestinal cancers, reflecting exposure to potential carcinogens as results of cooking. We used a validated food frequency questionnaire and a pretested cooking method questionnaire in 3 groups: 40 esophageal squamous cell carcinoma (ESCC) cases from a high-risk area in northeast of Iran, 40 healthy subjects from the same high-risk area, and 40 healthy subjects from a low-risk area in Southern Iran. We compared the frequency of boiling, grilling, and frying, and the frying score among these 3 groups. We also calculated "frying index" by multiplying the frequency of each fried food item by its frying score. Mean frying to boiling ratios were 18.2:1, 12.8:1, and 2.6:1 for cases, high-risk controls, and low-risk controls, respectively (P < 0.01). Reuse of cooking oil for frying was reported in 37.5% of the ESCC cases, 25% of high-risk controls, and 7.5% of low-risk controls (P < 0.001). Frying index was higher in the high-risk than in the low-risk controls (P < 0.001) and in cases than in the high-risk controls (P < 0.05) after adjusting for smoking, opium use, rural residence, education, and ethnicity. High-temperature cooking and frying may be associated with increased risk of ESCC in high-risk areas.

Opium: an emerging risk factor for gastric adenocarcinoma

Opium use has been associated with higher risk of cancers of the esophagus, bladder, larynx, and lung; however, no previous study has examined its association with gastric cancer. There is also little information on the associations between hookah (water pipe) smoking or the chewing of tobacco products and the risk of gastric cancer. In a case-control study in Golestan Province of Iran, we enrolled 309 cases of gastric adenocarcinoma (118 noncardia, 161 cardia and 30 mixed-location adenocarcinomas) and 613 matched controls. Detailed information on long-term use of opium, tobacco products and other covariates were collected using structured and validated lifestyle and food frequency questionnaires. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were obtained using conditional logistic regression models. Opium use was associated with an increased risk of gastric adenocarcinoma, with an adjusted OR (95% CI) of 3.1 (1.9-5.1), and this increased risk was apparent for both anatomic subsites (cardia and noncardia). There was a dose-response effect, and individuals with the highest cumulative opium use had the strongest association (OR: 4.5; 95% CI: 2.3-8.5). We did not find a statistically significant association between the use of any of the tobacco products and risk of gastric adenocarcinoma, overall or by anatomic subsite. We showed, for the first time, an association between opium use and gastric adenocarcinoma. Given that opium use is a traditional practice in many parts of the world, these results are of public health significance.

Prevalence, awareness and risk factors of hypertension in a large cohort of Iranian adult population

BACKGROUND

There is considerable variation in hypertension prevalence and awareness, and their correlates, across different geographic locations and ethnic groups. We performed this cross-sectional analysis on data from the Golestan Cohort Study (GCS).

METHODS

Enrollment in this study occurred in 2004-2008, and included 50,045 healthy individuals from Golestan Province in northeastern Iran. Hypertension was defined as a SBP at least 140 mmHg, a DBP at least 90 mmHg, a prior diagnosis of hypertension, or the use of antihypertensive drugs. Potential correlates of hypertension and its awareness were analyzed by logistic regression adjusted for sex, age, BMI, place of residence, literacy, ethnicity, physical activity, smoking, black and green tea consumption and wealth score.

RESULTS

Of the total cohort participants, 21,350 (42.7%) were hypertensive. Age-standardized prevalence of hypertension, using the 2001 WHO standard world population, was 41.8% (95% confidence interval: 38.3-45.2%). Hypertension was directly associated with female sex, increased BMI, Turkmen ethnicity, and lack of physical activity, and inversely associated with drinking black tea and wealth score. Among hypertensive patients, 46.2% were aware of their disease, 17.6% were receiving antihypertensive medication, and 32.1% of the treated patients had controlled hypertension. Hypertension awareness was greater among women, the elderly, overweight and obese patients, and those with a higher wealth score.

CONCLUSION

Hypertension is highly prevalent in rural Iran, many of the affected individuals are unaware of their disease, and the rate of control by antihypertensive medications is low. Increasing hypertension awareness and access to health services, especially among less privileged residents are recommended.