Multivitamin use and colorectal cancer incidence in a US cohort: does timing matter?

Multivitamins contain several nutrients, including folic acid, that are hypothesized to reduce the risk of colorectal cancer. Previous studies suggest that multivitamin use may reduce colorectal cancer risk but only after a long latency period. The authors examined the association between regular multivitamin use (four or more times per week) and colorectal cancer incidence among 145,260 men and women in the Cancer Prevention Study II Nutrition Cohort. Current multivitamin use was reported on a questionnaire at enrollment in 1992-1993. All participants had also reported multivitamin use on a questionnaire completed for a different study approximately 10 years earlier (in 1982). The authors observed 797 incident cases of colorectal cancer during follow-up from 1992 to 1997. After multivariate adjustment, regular multivitamin use at enrollment was not associated with risk of colorectal cancer (rate ratio = 1.04, 95% confidence interval: 0.87, 1.23), whereas regular multivitamin use 10 years before enrollment was associated with reduced risk (rate ratio = 0.71, 95% confidence interval: 0.57, 0.89). Regular multivitamin users 10 years before enrollment were at similarly reduced risk whether they were still regular multivitamin users at enrollment or had stopped. These results are consistent with the hypothesis that past, but not recent, multivitamin use may be associated with modestly reduced risk of colorectal cancer.     

Social inequalities and smoking-associated breast cancer — Results from a prospective cohort study

ObjectiveThe association between smoking and breast cancer has been found in most recent, large cohort studies. We wanted to investigate how smoking-associated breast cancer varies by level of education, a well-established measure of socioeconomic status.MethodsWe included 302,865 women with 7490 breast cancer cases. Participants were assigned to low, moderate or high level of education and analyzed by smoking status (ever/never), and stratified by birth cohorts (≤ 1950 >). We used Cox proportional hazard to estimate hazard ratios (HRs) and confidence intervals (CIs), adjusting for age, number of children, age at first childbirth, BMI, age at enrollment and physical activity.ResultsWomen born ≤ 1950 with low and moderate levels of education had a 40% increase in smoking-associated breast cancer risk (HR = 1.40, 95% CI 1.25–1.57 and HR = 1.14, 95% CI 1.05–1.24, respectively). Women in the same age group with high level of education did not have an increase in risk. No increased breast cancer risk was found among women born after 1950 for any level of education, when analyzed by smoking status. Longer duration of smoking before first childbirth was consistently associated with increasing risk of breast cancer in all three categories of education (all p for trends < 0.01).ConclusionSmoking for several years before first childbirth increases the risk of breast cancer, regardless of educational level.     

Socioeconomic inequalities in cancer incidence and mortality—a spatial analysis in Bremen, Germany

Aim

Several international studies have already investigated the influence of socioeconomic factors on the risk of cancer. For Germany, however, the data are still insufficient. We examined the effects of social differences on cancer incidence and mortality on the population of Bremen, a town in northwest Germany.

Subjects and methods

Data were obtained from the Bremen Cancer Registry, a population-based registry. The database comprised 27,430 incident cases, newly diagnosed between 2000 and 2006. The allocation of social class for each patient was based on the home address at the time of diagnosis, which led to the corresponding town district, which again could be linked to the “Bremen discrimination index.” Based on this index, cases were allocated to five categories, for which we compared standardized incidence ratios (SIR) and mortality ratios (SMR) for different cancers: prostate, breast, lung, colorectal, bladder, uterine, ovarian, cervical, malignant melanoma of the skin, non-melanoma skin cancer and all cancer sites summarized.

Results

The influence of social status was observed for different cancer sites. An inverse association was ascertained for all cancer sites (only men) and for tumors of the oral cavity and pharynx, and for lung, cervical and bladder cancers. A positive correlation was observed for female breast cancer, malignant melanoma, non-melanoma skin tumors and prostate cancer.

Conclusions

In spite of the methodical restrictions, our analyses suggest an association between social factors and cancer incidence and mortality. The results are in agreement with international studies. Many of the observed social class differences could probably be explained by known risk factors, such as smoking, alcohol consumption, diet and physical activity.     

Ten years of progress in the Hokkaido birth cohort study on environment and children’s health: cohort profile—updated 2013

The Hokkaido Study on Environment and Children’s Health is an ongoing cohort study that began in 2002. The study consists of two prospective birth cohorts, the Sapporo cohort (n = 514) and the Hokkaido large-scale cohort (n = 20,940). The primary goals of this study are to first examine the potential negative effects of perinatal environmental chemical exposures on birth outcomes, including congenital malformations and growth retardation; second, to evaluate the development of allergies, infectious diseases and neurodevelopmental disorders and perform longitudinal observations of the children’s physical development to clarify the causal relationship between these outcomes and environmental chemicals; third, to identify individuals genetically susceptible to environmental chemicals; finally, to identify the additive effects of various environmental factors in our daily life, such as secondhand smoke exposure or low folate intake during early pregnancy. In this paper, we introduce our recent progress in the Hokkaido study with a cohort profile updated in 2013. For the last ten years, we followed pregnant women and their offspring, measuring various environmental chemicals, i.e., PCB, OH-PCB and dioxins, PFCs (Perfluorinated Compounds), Organochlorine pesticides, Phthalates, bisphenol A and mercury. We discovered that the concentration of toxic equivalents (TEQ) of dioxin and other specific congeners of PCDF or PCDD have effects on birth weight, infants’ neurodevelopment and immune function. There were significant gender differences in these effects; our results suggest that male infants have more susceptibility to those chemical exposures than female infants. Interestingly, we found maternal genetic polymorphisms in AHR, CYP1A1 or GSTs that significantly modified the dioxin concentrations in maternal blood, suggesting different dioxin accumulations in the bodies of individuals with these genotypes, which would lead to different dioxin exposure levels. These genetic susceptibility factors influenced the body size of children born from mothers that either smoked or were passively exposed to tobacco smoke. Further studies investigating the correlation between epigenetics, the effects of intrauterine exposure to environmental chemicals and developmental factors related to health and disease are warranted.     

Mortality analyses in the updated French cohort of uranium miners (1946–2007)

Purpose

The objectives are to analyze mortality risks in the extended follow-up of the French uranium miners’ cohort and to examine their potential relation to occupational exposure to ionizing radiation (IR).

Methods

The total cohort includes 5,086 uranium miners employed in the CEA-COGEMA group and followed up from 1946 to 2007. Vital status, causes of death, and cumulative radon exposures were recorded. The post-55 subcohort includes 3,377 miners first employed after 1955, for whom long-lived radionuclides (LLR) and external gamma-ray exposure were also recorded. External mortality analyses were performed by computing standardized mortality ratios (SMR). Excess relative risks (ERRs) due to IR exposures were estimated from Poisson regression models.

Results

The miners included in the total cohort were followed up for 35.4 years and exposed to 36.6 working level months (WLM) on average. There was no evidence of a difference in overall mortality between miners and the general French male population. Miners had a statistically significant excess mortality rate from lung cancer (SMR = 1.34 [95 % CI 1.16–1.53]) and from kidney cancer (SMR = 1.60 [1.03–2.39]). Cumulative radon exposure was significantly associated with lung cancer risk (ERR/100 WLM = 0.71 [0.31–1.30]) and cerebrovascular risk (ERR/100 WLM = 0.41 [0.04–1.03]). In the post-55 subcohort, this excess mortality from lung cancer remained associated with exposure to radon, and also with exposure to LLR and external gamma rays.

Conclusions

The analyses in the extended follow-up strengthen the results previously observed among French uranium miners about their excess risk of mortality and its association with their occupational IR exposure.

     

Neighbourhood greenness and birth outcomes in a Swedish birth cohort – A short communication

The present study investigated whether associations between greenness and birth outcomes can be detected in children belonging to a Swedish birth cohort (BAMSE). Normalized difference vegetation index (NDVI) within a 500 m buffer zone around maternal address was used as estimate of greenness. Ordinary least squares and quantile regression models were performed to investigate associations between neighbourhood NDVI and birthweight (n = 2619), birth length (n = 2490) and head circumference (n = 2243). Logistic regression analyses were used to detect the association between NDVI and odds of being born as “small-” or “large-for-gestational-age”. There were no clear associations between NDVI and birth weight in the total sample. However, in a suburban sub-sample, increased NDVI levels were significantly associated with elevated birthweight of small new-borns (β_{2nd percentile} = 276 g, 95% CI 61 to 492, p = 0.012), and significantly reduced the odds ratio (OR) for children being born as small-for-gestational-age (OR = 0.31 95% CI 0.1 to 1, p = 0.049). No significant associations were found between NDVI and birth length or head circumference. In conclusion, neighbourhood greenness appears not to be associated with birthweight as such, but rather decrease the odds of being born underweight, in particular in suburban areas.     

Consumption of alcohol and risk of cancer among men: a 30 year cohort study in Lithuania

Studies have indicated hazardous consumption of large quantities of alcohol among adults in Lithuania. We assessed the associations of alcohol consumption at baseline with cancer incidence among men in a population-based cohort study, using Cox models adjusted for smoking, education and body mass index. Attained age was used as a time-scale. During follow-up (1978–2008) 1,698 men developed cancer. A higher amount of alcohol consumption (≥140.1 g/week vs. 0.1–10.0 g/week) was positively associated with increased risk of total cancer [hazard ratio (HR) = 1.36, 95 % confidence interval (95 % CI) 1.11, 1.65], upper aerodigestive tract cancer (HR = 2.79, 95 % CI 1.23, 6.34) and alcohol-related cancers (i.e. oral cavity, pharynx, larynx, oesophagus, colorectal and liver cancer) (HR = 1.88, 95 % CI 1.25, 2.85). Compared to occasional drinkers (a few times/year), drinkers 2–7 times/week showed an increased risk of total (HR = 1.45, 95 % CI 1.16, 1.83), alcohol-related (HR = 1.83 95 % CI 1.14, 2.93) and other cancers (HR = 1.35, 95 % CI 1.04, 1.76). Our results showed no statistically significant associations between quantity of alcohol intake per one occasion and risk of cancer. About 13 % of total, 35 % of upper aerodigestive tract, 22 % of alcohol-related and 10 % of other cancer cases were due to alcohol consumption in this cohort of men.     

Mortality after discharge from long-term psychiatric care in Scotland, 1977 – 94: a retrospective cohort study

Background

Recent United Kingdom strategies focus on preventable suicide deaths in former psychiatric in-patients, but natural causes of death, accidents and homicide may also be important. This study was intended to find the relative importance of natural and unnatural causes of death in people discharged from long-term psychiatric care in Scotland in 1977 –1994.

Methods

People discharged alive from psychiatric hospitals in Scotland in 1977 – 94 after a stay of one year or longer were identified using routine hospital records. Computer record linkage was used to link hospital discharges to subsequent death records. Mortality was described using a person-years analysis, and compared to the general population rates.

Results

6,776 people were discharged in the time period. 1,994 people (29%) died by the end of follow-up, 732 more deaths than expected. Deaths from suicide, homicide, accident and undetermined cause were increased, but accounted for only 197 of the excess deaths. Deaths from respiratory disease were four times higher than expected, and deaths from other causes, including cardiovascular disease, were also elevated.

Conclusion

Suicide is an important cause of preventable mortality, but natural causes account for more excess deaths. Prevention activities should not focus only on unnatural causes of death.

     

Mortality rates and causes of death in a cohort of HIV-infected and uninfected women, 1993–1999

HIV/AIDS-associated and non-HIV/AIDS-associated death rates and causes of death between 1993 and 1999 were examined in 885 HIV-infected women and 425 uninfected women of the HIV Epidemiology Research Study cohort. Causes of death were determined by review of death certificates and the National Death Index. Adjusted bazard ratios were calculated for mortality risk factors. In the 885 HIV-infected women and 425 uninfected women, 234 deaths and 8 deaths, respectively, occurred by December 31, 1999. All-cause death rates in the HIV-infected women were unchanged between the pre-HAART (1993–1996) and HAART eras (1997–1999) —5.1 versus 5.4 deaths per 100 person-years (py). AIDS as a cause of death decreased from 58% of all deaths in 1996 to 19% in 1999, while HAART use increased to 42% by the end of 1999. In spite of the modest proportion ever using HAART, HIV-related mortality rates did decline, particularly in women with CD4+cell counts less than 200/mm³. Drug-related factors were prominent: for the 129 non-AIDS-defining deaths, hepatitis C positivity (relative bazard [RH] 2.6, P<0.001) and injection drug use (RH 1.7, P=0.02) were strong predictors of mortality, but were not significant in the Cox model for 105 AIDS-defining deaths (RH 0.9, P>30 and RH 0.7, P>.30, respectively. The regression analysis findings, along with the high percentage of non-AIDS deaths attributable to illicit drug use, suggest that high levels of drug use in this population offset improvements in mortality from declining numbers of deaths due to AIDS. Supported by cooperative agreements No. U64/CCU106795, U64/CCU206798, U64/CCU306802, and U64/CCU506831 with the Centers for Disease Control and Prevention including supplementary support from the National Institute on Drug Abuse. Centers for Disease Control and Prevention, Division of HIV     

Smoking and susceptibility to rheumatoid arthritis in a Swedish population-based case–control study

Smoking is one of the most established risk factors for rheumatoid arthritis (RA). The aim of this study was to estimate how age at smoking debut, smoking cessation, duration, intensity, and cumulative dose of smoking influence the risk of developing anti-citrullinated peptide antibodies (ACPA) positive and ACPA negative RA. The present report is based on a Swedish population-based, case–control study with incident cases of RA (3655 cases, 5883 matched controls). Using logistic regression models, subjects with different smoking habits were compared regarding risk of developing the two variants of RA, by calculating odds ratios (OR) with 95% confidence intervals (CI). Smoking increased the risk of developing both ACPA positive (OR 1.9, 95% CI 1.7–2.1) and ACPA negative RA (OR 1.3, 95% CI 1.2–1.5). For both subsets of RA, there seemed to be a threshold (~ 2.5 pack years for ACPA positive RA and ~ 5 pack years for ACPA negative RA) below which no association between smoking and RA occurred. A dose–response association was observed between cumulative dose of smoking and risk of developing ACPA positive RA (p value for trend < 0.0001). Duration of smoking had a higher influence on the association between smoking and RA than did intensity of smoking. For both subsets of RA, the detrimental effect of smoking decreased after smoking cessation. Twenty years after smoking cessation, there was no longer an association between smoking and risk of ACPA negative RA, whereas the association between smoking and ACPA positive RA risk persisted and was dependent on the cumulative dose of smoking. Smoking increases the risk of both subsets of RA with a more pronounced influence on the risk of ACPA positive RA. Preventive measures in order to reduce smoking are essential and may result in a decline in RA incidence.     

An updated historical cohort mortality study of workers exposed to asbestos in a refitting shipyard, 1947�C2007

Purpose

To evaluate the long-term health effects of occupational asbestos exposure, an updated historical cohort mortality study of workers at a refitting shipyard was undertaken.

Methods

The cohort consisted of 249 male ship repair workers (90 laggers, 159 boiler repairers). To determine relative excess mortality, standardized mortality ratios (SMRs) were calculated using mortality rates among the Japanese male population. Mortality follow-up of study subjects was performed for the period from 1947 till the end of 2007.

Results

We identified the vital status of 87 (96.7%) laggers and 150 (94.3%) boiler repairers. Of these, 63 (72.4%) and 95 (63.3%), respectively, died. Laggers, who had handled asbestos materials directly, showed a significantly elevated SMR of 2.64 (95% confidence interval [CI]: 1.06?C5.44) for lung cancer and 2.49 (95% CI: 1.36?C4.18) for nonmalignant respiratory diseases. Boiler repairers, who had many opportunities for secondary exposure to asbestos and a few for direct exposure, showed no significant elevation in SMR for lung cancer but a significantly elevated SMR of 1.78 (95% CI: 1.06?C2.81) for nonmalignant respiratory diseases. In an analysis according to duration of employment, there was a significantly elevated SMR of nonmalignant respiratory diseases in the longer working years group. Among workers from both jobs, no deaths caused by mesothelioma in addition to those in the original study were found and no subject died from larynx cancer.

Conclusion

This updated study confirmed a significant excess of asbestos-related mortality from diseases such as lung cancer and nonmalignant respiratory diseases among workers in a refitting shipyard in Japan.     

High body mass index and cancer risk—a Mendelian randomisation study

High body mass index (BMI) has been associated with increased risk of some cancer. Whether these reflect causal associations is unknown. We examined this issue. Using a Mendelian randomisation approach, we studied 108,812 individuals from the general population. During a median of 4.7 years of follow-up (range 0–37), 8002 developed non-skin cancer, 3347 non-melanoma skin cancer, 1396 lung cancer, 637 other smoking related cancers, 1203 colon cancer, 159 kidney cancer, 1402 breast cancer, 1062 prostate cancer, and 2804 other cancers. Participants were genotyped for five genetic variants associated with BMI. Two Danish general population studies, the Copenhagen General Population and the Copenhagen City Heart Study. In observational analyses, overall risk of non-melanoma skin cancer was 35 % (95 % confidence interval 28–42 %) lower and risk of lung cancer 32 % (19–43 %) lower in individuals with a BMI ≥ 30 versus 18.5–24.9 kg/m². Corresponding risk of breast cancer was 20 % (0–44 %) higher in postmenopausal women. BMI was not associated with risk of colon, kidney, other smoking related cancers, prostate cancer, or other cancers. In genetic analyses, carrying 7–10 versus 0–4 BMI increasing alleles was associated with a 3 % higher BMI (P < 0.001), but not with risk of cancer. In instrumental variable analysis for a 10 kg/m² higher genetically determined BMI the odds ratio for any non-skin cancer was 1.16 (0.64–2.09), with a corresponding observational estimate of 0.94 (0.88–1.01). Using 108,812 individuals from the general population, we found that observationally high BMI was associated with lower risk of lung and skin cancer overall and with higher risk of breast cancer in postmenopausal women, but not with other types of cancer. BMI increasing alleles were not associated with risk of cancer, and results do not support causal associations. Power to test associations for some cancer sites was low.     

High folate intake is associated with lower breast cancer incidence in postmenopausal women in the Malmö Diet and Cancer cohort

BACKGROUND: Epidemiologic studies of associations between folate intake and breast cancer are inconclusive, but folate and other plant food nutrients appear protective in women at elevated risk. OBJECTIVE: The objective was to examine the association between folate intake and the incidence of postmenopausal breast cancer. DESIGN: This prospective study included all women aged >or=50 y (n = 11699) from the Malm? Diet and Cancer cohort. The mean follow-up time was 9.5 y. We used a modified diet-history method to collect nutrient intake data. At the end of follow-up, 392 incident invasive breast cancer cases were verified. We used proportional hazard regression to calculate hazard ratios (HRs). RESULTS: Compared with the lowest quintile, the incidence of invasive breast cancer was reduced in the highest quintile of dietary folate intake (HR: 0.56; 95% CI: 0.35, 0.90; P for trend = 0.02); total folate intake, including supplements (HR: 0.56; 95% CI: 0.34, 0.91; P for trend = 0.006); and dietary folate equivalents (HR: 0.59; 95% CI: 0.36, 0.97; P for trend = 0.01). CONCLUSION: A high folate intake was associated with a lower incidence of postmenopausal breast cancer in this cohort.     

Breast cancer risk and night shift work in a case–control study in a Spanish population

Epidemiologic and animal data indicate that night shift work might increase the risk for breast cancer. We evaluated the association of night work with different clinical types of breast cancer in a population based case–control study (MCC-Spain study) taking into account chronotype, an individual characteristic that may relate to night shift work adaptation. Lifetime occupational history was assessed by face-to-face interviews and shift work information was available for 1708 breast cancer cases and 1778 population controls from 10 Spanish regions, enrolled from 2008 to 2013. We evaluated three shift work domains, including shift work type (permanent vs rotating), lifetime cumulative duration and frequency. We estimated odds ratios (OR) for night work compared to day work using unconditional logistic regression models adjusting for confounders. Having ever worked permanent or rotating night shift was associated with an increased risk for breast cancer compared to day workers [odds ratio (OR) 1.18; 95 % CI 0.97, 1.43]. Chronotype was differentially associated with breast cancer depending on the duration of night shift work. Risk was higher in women with invasive tumors (OR 1.23; 95 % CI 1.00, 1.51) and for estrogen and progestagen positive tumors among premenopausal women (OR 1.44; 95 % CI 1.05, 1.99). Having ever performed night shift was associated with a small increased risk for breast cancer and especially in subgroups of women with particular hormone related characteristics.     

AIDS incidence and survival in a hospital-based cohort of asymptomatic HIV seropositive patients in São Paulo, Brazil

BACKGROUND: In spite of the high incidence of AIDS in Brazil, few studies have tried to evaluate the prognosis of asymptomatic HIV seropositive Brazilian patients. METHODS: A hospital outpatient facility-based cohort of HIV seropositive asymptomatic subjects was followed to determine their probability of remaining AIDS-free at 2 and 4 years of follow-up, as well as the one-year estimated cumulative probability of survival for the AIDS incident cases. The cohort was made up of all asymptomatic HIV seropositive subjects referred to the Immunology Branch of a large university hospital in S?o Paulo, Brazil, between 1985 and June 1997. RESULTS: The cumulative probability of remaining free from AIDS was 79% (+/- 3.7% SE) at 2 years, and 64.4% (+/- 5.1% SE) at 4 years after first known positive anti-HIV serology. Women had a marginally significant better probability of remaining AIDS-free after both 2 and 4 years of known seropositivity, as compared with men. There were no significant differences in the prognosis of the infection by age; the only single parameter associated with better prognosis was an initial CD4+ count > or =350/microl. The probability of survival one year after the diagnosis of AIDS was 78%, and the 50% estimated probability of survival was 19 months. Older patients (aged > or =35 years) had a better prognosis, as suggested by their longer survival estimates (P = 0.06). CONCLUSIONS: The probability of survival with AIDS observed in this study was higher than in the few previously published estimates for Brazil. However, since the time frame was so wide, it may not be entirely comparable with earlier studies. Some likely explanations for this possibly better prognosis could include more efficient prophylaxis for opportunistic diseases, as well as an increase in the availability of anti-retroviral drugs. The 8% incidence of AIDS at 2 years observed in this study for those individuals whose initial CD4+ count was > or =350/ml was close to that found in a large international epidemiological study of seroconverters.