Philip R. Taylor

Prospective study of risk factors for esophageal and gastric cancers in the Linxian general population trial cohort in China

Esophageal cancer incidence and mortality rates in Linxian, China are among the highest in the world. We examined risk factors for esophageal squamous cell carcinoma (ESCC), gastric cardia cancer (GCC), and gastric noncardia cancer (GNCC) in a population‐based, prospective study of 29,584 adults who participated in the Linxian General Population Trial. All study participants completed a baseline questionnaire that included questions on demographic characteristics, personal and family history of disease, and lifestyle factors. After 15 years of follow‐up, a total of 3,410 incident upper gastrointestinal cancers were identified, including 1,958 ESCC, 1,089 GCC and 363 GNCC. Cox proportional hazard models were used to estimate risks. Increased age and a positive family history of esophageal cancer (including ESCC or GCC) were significantly associated with risk at all 3 cancer sites. Additional risk factors for ESCC included being born in Linxian, increased height, cigarette smoking and pipe smoking; for GCC, male gender, consumption of moldy breads and pipe smoking; and for GNCC, male gender and cigarette smoking. Protective factors for ESCC included formal education, water piped into the home, increased consumption of meat, eggs and fresh fruits and increased BMI; for GCC, formal education, water piped into the home, increased consumption of eggs and fresh fruits and alcohol consumption; and for GNCC, increased weight and BMI. General socioeconomic status (SES) is a common denominator in many of these factors and improving SES is a promising approach for reducing the tremendous burden of upper gastrointestinal cancers in Linxian.

SELECT: the selenium and vitamin E cancer prevention trial.

PURPOSE Growing evidence suggests that both selenium and vitamin E may reduce the risk of prostate cancer. SELECT is a randomized, prospective, double-blind study designed to determine if selenium and vitamin E can reduce the risk of prostate cancer among healthy men. MATERIALS AND METHODS The preclinical and epidemiologic evidence regarding chemoprevention with selenium and vitamin E were reviewed. Secondary analyses from randomized trials of both agents were included in the analysis. Data from these analyses as well as evidence from the Prostate Cancer Prevention Trial were used to develop the schema of SELECT. RESULTS Preclinical, epidemiologic, and Phase III data suggest that both selenium and vitamin E have potential efficacy in prostate cancer prevention. The experience of the Prostate Cancer Prevention Trial and the rapid accrual of SELECT during its first year demonstrate the interest and dedication of healthy men to long-term studies of cancer prevention. A total of 32,400 men are planned to be randomized in SELECT. CONCLUSIONS SELECT is the second large-scale study of chemoprevention for prostate cancer. Enrollment began in 2001 with final results anticipated in 2013.

Prospective study of tooth loss and incident esophageal and gastric cancers in China

AbstractObjective: To determine the association between tooth loss and the risk of developing esophageal squamous cell carcinoma, gastric cardia adenocarcinoma, or gastric non-cardia adenocarcinoma in a prospective study. Methods: Cox proportional hazards regression was used to examine these associations in a 28,868-person cohort followed prospectively for 5.25 years. The baseline questionnaire included questions regarding tooth loss, and individuals reporting lost teeth had their teeth counted by study personnel. The analytic cohort included 620 esophagus, 431 gastric cardia, and 102 gastric non-cardia cancer cases. Results: Tooth loss was associated with a significantly elevated risk of developing all three cancers. When examined as median splits, tooth loss was associated with a relative risk (RR) (95% confidence interval, CI) of 1.3 (1.1–1.6) in the esophagus, 1.3 (1.0–1.6) in the gastric cardia, and 1.8 (1.1–3.0) in the gastric non-cardia. Further analysis demonstrated that this increased risk was most strongly associated with the loss of the first few teeth and was primarily confined to the younger members of our cohort. Conclusions: In this cohort tooth loss increased the risk of developing upper gastrointestinal cancer. We hypothesize that this may be related to alterations in oral bacterial flora and subsequent increases in the in-vivo production of carcinogens such as nitrosamines.

The Linxian trials: mortality rates by vitamin-mineral intervention group.

Two randomized nutrition intervention trials were conducted in Linxian, an area of north central China with some of the worlds highest rates of esophageal and stomach cancer and a population with a chronically low intake of several nutrients. One trial used a factorial design that allowed us to assess the effects in nearly 30,000 participants of daily supplementation with four nutrient combinations: retinol and zinc; riboflavin and niacin; vitamin C and molybdenum; and beta-carotene, alpha-tocopherol, and selenium. The second trial provided daily multiple vitamin-mineral supplementation or placebo in 3318 persons with esophageal dysplasia, a precursor to esophageal cancer. After supplements were given for 5.25 y in the general population trial, small but significant reductions in total [relative risk (RR) = 0.91] and cancer (RR = 0.87) mortality were observed in subjects receiving beta-carotene, alpha-tocopherol, and selenium but not the other nutrients. The reductions were greater in women than men, and in those under compared with over the age of 55; however, differences by sex or age were not significant. After multiple vitamin and mineral supplements were given for 6 y in the smaller dysplasia trial, reductions in total (RR = 0.93) and cancer (RR = 0.96) mortality were observed but these were not significant. The largest reductions were for cerebrovascular disease mortality, but the effects differed by sex: a significant reduction was observed in men (RR = 0.45) but not women (RR = 0.90). Restoring adequate intake of certain nutrients may help to lower the risk of cancer and other diseases in this high-risk population.

Helicobacter pylori Seropositivity as a Risk Factor for Pancreatic Cancer

BACKGROUND Pancreatic cancer is among the most fatal cancers worldwide and one for which few preventable risk factors have been established. Gastric carriage of Helicobacter pylori, particularly cytotoxin-associated gene-A-positive (CagA+) strains, is known to be a risk factor for peptic ulcer disease and gastric cancer and may have a similar etiologic relationship with pancreatic cancer. METHODS We investigated the association of H. pylori carriage and exocrine pancreatic cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29 133 male Finnish smokers aged 50-69 years at baseline. Case subjects (n = 121) were matched on date of baseline serum collection, study center, age, trial intervention, and completion of the dietary questionnaire to 226 control subjects who were alive at the time the matching case subject was diagnosed and who remained free of cancer, during up to 10 years of follow-up. Levels of immunoglobulin G antibodies to H. pylori whole-cell and CagA+ antigens from stored baseline serum were measured by enzyme-linked immunosorbent assay. Smoking-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by use of conditional logistic regression. Statistical tests were two-sided. RESULTS Seroprevalence of H. pylori was 82% and 73% among case and control subjects, respectively. Compared with seronegative subjects, those with H. pylori or CagA+ strains were at statistically significantly elevated risk of pancreatic cancer (OR = 1.87 [95% CI = 1.05 to 3.34]; OR = 2.01 [95% CI = 1.09 to 3.70], respectively). CONCLUSIONS Our findings support a possible role for H. pylori carriage in the development of exocrine pancreatic cancer.

Fruits, Vegetables, and Antioxidants and Risk of Gastric Cancer among Male Smokers

The effect of consumption of fruits, vegetables, and antioxidants on the incidence of gastric cancer is inconclusive. In this prospective cohort study, we report the association of dietary intake of fruits, vegetables, antioxidants, and baseline serum levels of antioxidants with subsequent incidence of gastric cardia cancer (GCC) and gastric noncardia cancer (GNCC). Participants of this study were 29,133 male smokers recruited into the α-Tocopherol, β-Carotene Cancer Prevention study between 1985 and 1988. At baseline, a self-administered food use questionnaire with 276 food items was used to assess dietary intake. Baseline serum samples were stored at −70°C. During a median follow-up of 12 years, 243 incident gastric adenocarcinomas (64 GCC and 179 GNCC) were diagnosed in this cohort, of whom 220 (57 GCC and 163 GNCC) had complete dietary information. For GCC, high dietary intake of retinol was protective [hazard ratio (HR), 0.46; 95% confidence interval (95% CI), 0.27-0.78], but high intake of α-tocopherol (HR, 2.06; 95% CI, 1.20-3.54) and γ-tocopherol (HR, 1.94; 95% CI, 1.13-3.34) increased risk. For GNCC, higher intakes of fruits (HR, 0.51; 95% CI, 0.37-0.71), vitamin C (HR, 0.60; 95% CI, 0.41-0.86), α-tocopherol (HR, 0.78; 95% CI, 0.55-1.10), γ-tocopherol (HR, 0.69; 95% CI, 0.49-0.96), and lycopene (HR, 0.67; 95% CI, 0.47-0.95) were protective. Our results suggest a difference in the effect of some of these exposures on GCC and GNCC. Tocopherols were associated with higher risk of GCC, whereas dietary intake of fruits, vitamin C, tocopherols, and lycopene seemed protective for GNCC.

Polychlorinated biphenyls: influence on birthweight and gestation

Fifty-one infants born to women employed at two capacitor manufacturing facilities with a history of high exposure to polychlorinated biphenyls (PCBs) had a mean birthweight of 153 grams less than that of 337 infants born to women who had worked in low-exposure areas (90 per cent confidence interval, -286 to -20 g); mean gestational age was 6.6 days shorter in the high-exposure infants (90 per cent CI, -10.3 to -2.9 days). After adjusting for gestational age, the difference in birthweight was markedly reduced, indicating that the observed reduction in birthweight was due mainly to shortening of gestational age in the high-exposure group.

Serum and Dietary Vitamin E in Relation to Prostate Cancer Risk

α-Tocopherol supplementation (50 mg daily for 5-8 years) reduced prostate cancer incidence by 32% in the α-Tocopherol, β-Carotene Cancer Prevention Study. We investigated whether serum α-tocopherol or intake of vitamin E (eight tocopherols and tocotrienols) was associated with prostate cancer risk with up to 19 years of follow-up in the α-Tocopherol, β-Carotene Cancer Prevention Study cohort. Of the 29,133 Finnish male smokers, ages 50 to 69 years recruited into the study, 1,732 were diagnosed with incident prostate cancer between 1985 and 2004. Baseline serum α-tocopherol was measured by high-performance liquid chromatography and the components of vitamin E intake were estimated based on a 276-item food frequency questionnaire and food chemistry analyses. Proportional hazard models were used to determine multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI). Higher serum α-tocopherol was associated with reduced risk of prostate cancer (RR, 0.80; 95% CI, 0.66-0.96 for highest versus lowest quintile; Ptrend = 0.03) and was strongly and inversely related to the risk of developing advanced disease (RR, 0.56; 95% CI, 0.36-0.85; Ptrend = 0.002). The inverse serum α-tocopherol-prostate cancer association was greater among those who were supplemented with either α-tocopherol or β-carotene during the trial. There were no associations between prostate cancer and the individual dietary tocopherols and tocotrienols. In summary, higher prediagnostic serum concentrations of α-tocopherol, but not dietary vitamin E, was associated with lower risk of developing prostate cancer, particularly advanced prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1253–9)

Family history of cancer and risk for esophageal and gastric cancer in Shanxi, China

BackgroundFamily history (FH) by different relative types and risk of upper gastrointestinal (UGI) cancers has been only rarely reported; the data on UGI cancer survival are sparse.Methods600 esophageal squamous cell carcinoma (ESCC) cases, 598 gastric cardia adenocarcinoma cases, and 316 gastric non-cardia adenocarcinoma cases, and 1514 age-, gender-, and neighborhood-matched controls were asked for FH in first degree relatives and non-blood relatives. Odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regressions, and hazard ratios (HRs) from Cox proportional hazard regressions were estimated.ResultsIncreased ESCC risk was associated with FH of any cancer (OR = 1.72, 95% CI = 1.39–2.12), FH of any UGI cancer (OR = 2.28, 95%CI = 1.77–2.95) and FH of esophageal cancer (OR = 2.84, 95%CI = 2.09–3.86), but not FH of non-UGI cancer. Individuals with two or more affected first-degree relatives had 10-fold increased ESCC risk. FH of gastric cardia cancer was associated with an increased risk of all three cancers. Cancer in non-blood relatives was not associated with risk of any UGI cancer. FH of UGI cancer was associated with a poorer survival rate among younger ESCC cases (HR = 1.82, 95%CI = 1.01–3.29).ConclusionThese data provide strong evidence that shared susceptibility is involved in esophageal carcinogenesis and also suggest a role in prognosis.

Treatment of osteoarthritis of the knee with transcutaneous electrical nerve stimulation

Abstract Ten patients with pain due to osteoarthritis of the knee were treated in a double‐blind cross‐over study with two weeks of transcutaneous electrical nerve stimulation (TENS) and placebo. There was statistically significant pain relief by TENS and half of the patients chose to continue using TENS for pain control after the test month. However, at one years follow‐up, only two patients had sufficient benefit to continue using the device.