Glycemic index, glycemic load and endometrial cancer risk: results from the Australian National Endometrial Cancer study and an updated systematic review and meta-analysis

Purpose

The relationship between habitual consumption of foods with a high glycemic index (GI) and/or a diet with a high glycemic load (GL) and risk of endometrial cancer is uncertain, and relatively few studies have investigated these associations. The objectives of this study were to examine the association between GI/GL and risk of endometrial cancer using data from an Australian population-based case–control study and systematically review all the available evidence to quantify the magnitude of the association using meta-analysis.

Methods

The case–control study included 1,290 women aged 18–79 years with newly diagnosed, histologically confirmed endometrial cancer and 1,436 population controls. Controls were selected to match the expected Australian state of residence and age distribution (in 5-year bands) of cases. For the systematic review, relevant studies were identified by searching PubMed and Embase databases through to July 2011. Random-effects models were used to calculate the summary risk estimates, overall and dose–response.

Results

In our case–control study, we observed a modest positive association between high dietary GI (OR 1.43, 95 % CI 1.11–1.83) and risk of endometrial cancer, but no association with high dietary GL (OR 1.15, 95 % CI 0.90–1.48). For the meta-analysis, we collated information from six cohort and two case–control studies, involving a total of 5,569 cases. The pooled OR for the highest versus the lowest intake category of GI was 1.15 (0.95–1.40); however, there was significant heterogeneity (p 0.004) by study design (RR 1.00 [95 % CI 0.87–1.14] for cohort studies and 1.56 [95 % CI 1.21–2.02] for case–control studies). There was no association in the dose–response meta-analysis of GI (RR per 5 unit/day increment of GI 1.00, 95 % CI 0.97–1.03). GL was positively associated with endometrial cancer. The pooled RR for the highest versus the lowest GL intake was 1.21 (95 % CI 1.09–1.33) and 1.06 (95 % CI 1.01–1.11) per 50 unit/day increment of GL in the dose–response meta-analysis.

Conclusion

The pooled results from observational studies, including our case–control results, provide evidence of a modest positive association between high GL, but not GI, and endometrial cancer risk.     

Optimal nutrition and the ever-changing dietary landscape: a conference report

Purpose

Laboratory studies suggested that caffeine and other nutrients contained in coffee and tea may protect against non-melanoma skin cancer (NMSC). However, epidemiological studies conducted so far have produced conflicting results.

Methods

We performed a literature review and meta-analysis of observational studies published until February 2016 that investigated the association between coffee and tea intake and NMSC risk. We calculated summary relative risk (SRR) and corresponding 95 % confidence intervals (95 % CI) by using random effects with maximum likelihood estimation.

Results

Overall, 37,627 NMSC cases from 13 papers were available for analysis. Intake of caffeinated coffee was inversely associated with NMSC risk (SRR for those in the highest vs. lowest category of intake: 0.82, 95 % CI 0.75–0.89, I ² = 48 %), as well as intake of caffeine (SRR 0.86, 95 % CI 0.80–0.91, I ² = 48 %). In subgroup analysis, these associations were limited to the basal cell cancer (BCC) histotype. There was no association between intake of decaffeinated coffee (SRR 1.01, 95 % CI 0.85–1.21, I ² = 0) and tea (0.88, 95 % CI 0.72–1.07, I ² = 0 %) and NMSC risk. There was no evidence of publication bias affecting the results. The available evidence was not sufficient to draw conclusions on the association between green tea intake and NMSC risk.

Conclusions

Coffee intake appears to exert a moderate protective effect against BCC development, probably through the biological effect of caffeine. However, the observational nature of studies included, subject to bias and confounding, suggests taking with caution these results that should be verified in randomized clinical trials.

     

Coffee and caffeine intake and incidence of type 2 diabetes mellitus: a meta-analysis of prospective studies

Purpose

Coffee and caffeine have been linked to type 2 diabetes mellitus (T2DM). A dose–response meta-analysis of prospective studies was conducted to assess the association between coffee and caffeine intake and T2DM incidence.

Methods

Pertinent studies were identified by a search of PubMed and EMBASE. The fixed- or random-effect pooled measure was selected based on between-study heterogeneity. Dose–response relationship was assessed by restricted cubic spline.

Results

Compared with the lowest level, the pooled relative risk (95 % CI) of T2DM was 0.71 (0.67–0.76) for the highest level of coffee intake (26 articles involving 50,595 T2DM cases and 1,096,647 participants), 0.79 (0.69–0.91) for the highest level of decaffeinated coffee intake (10 articles involving 29,165 T2DM cases and 491,485 participants) and 0.70 (0.65–0.75) for the highest level of caffeine intake (6 articles involving 9,302 T2DM cases and 321,960 participants). The association of coffee, decaffeinated coffee and caffeine intake with T2DM incidence was stronger for women than that for men. A stronger association of coffee intake with T2DM incidence was found for non-smokers and subjects with body mass index <25 kg/m². Dose–response analysis suggested that incidence of T2DM decreased by 12 % [0.88 (0.86–0.90)] for every 2 cups/day increment in coffee intake, 11 % [0.89 (0.82–0.98)] for every 2 cups/day increment in decaffeinated coffee intake and 14 % [0.86 (0.82–0.91)] for every 200 mg/day increment in caffeine intake.

Conclusions

Coffee and caffeine intake might significantly reduce the incidence of T2DM.     

Caffeine intake and risk of basal cell and squamous cell carcinomas of the skin in an 11-year prospective study

Purpose

Caffeine may repair skin damage induced by excessive exposure to ultraviolet light. The purpose of this study was to investigate the association between caffeine intake and incidence of basal cell (BCC) and squamous cell carcinoma (SCC). We also assessed the associations between coffee consumption and incidence of these skin cancers.

Methods

Caffeine intake and consumption of coffee were estimated from food frequency questionnaires assessed in 1992, 1994, and 1996 among 1,325 randomly selected adult residents of a subtropical Australian community. All histologically confirmed tumours of BCC and SCC occurring between 1997 and 2007 were recorded. Associations with BCC and SCC were assessed using Poisson and negative binomial regression models and were adjusted for confounders including skin type and indicators of past sun exposure.

Results

There was no association between total caffeine intake and incidence of BCC or SCC. Participants with prior skin cancers, however, had a 25 % lower risk of BCC if they were in the highest tertile of total caffeine intake (equivalent to daily consumption of four cups of regular coffee) compared with the lowest tertile (multivariable RR 0.75; 95 % CI 0.57–0.97, P trend = 0.025). There was no dose–response relationship with SCC. Consumption of neither caffeinated nor decaffeinated coffee was associated with BCC or SCC.

Conclusions

Among people with prior skin cancers, a relatively high caffeine intake may help prevent subsequent BCC development. However, caffeine intake appears not to influence the risk of SCC.     

Systematic review and meta-analysis: dairy consumption and hepatocellular carcinoma risk

Aim

This study conducts a systematic review and meta-analysis to assess the association between dairy consumption and hepatocellular carcinoma (HCC) risk.

Subjects and methods

The association between consumption of overall dairy, specific dairy products (such as milk, cheese, butter, yoghurt, condensed milk, whey, casein, lactose) and HCC risk has not been assessed before. This association between dairy consumption and HCC risk has been reported in several epidemiological studies, but results were controversial and inconsistent. The PubMed, EMBASE and Cochrane databases were searched for relevant studies published up to September 20, 2015. The relative risks (RRs) and odds ratios (ORs) with 95% confidence intervals (CIs) for dairy consumption associated with HCC risk were extracted from each included cohort as well as case-control study. In our study, the pooled RR was obtained using the random-effects model. Heterogeneity was evaluated by Q and I ² statistics.

Results

A total number of 1,084,666 participants and 2041 HCC patients from three cohort studies and five case-control studies were included in this meta-analysis. The pooled RR of dairy was 1.38 (95% CI: 1.00–1.91, p = 0.00) in all studies. The pooled RR of milk, yoghurt, and cheese was 1.13 (95% CI: 0.67–1.88, p = 0.00), 0.40 (95% CI: 0.14–1.14, p = 0.00) and 1.45 (95% CI: 1.02–2.07, p = 0.80), respectively.

Conclusions

This meta-analysis indicates that consumption of overall dairy may be associated with increased HCC risk and a risk factor involved in the etiology of HCC.

     

Cheese consumption and risk of cardiovascular disease: a meta-analysis of prospective studies

Purpose

Cheese contains a high content of saturated fatty acids but also lists of potentially beneficial nutrients. How long-term cheese consumption affects the development of cardiovascular disease (CVD) is unclear. A meta-analysis of prospective observational studies was conducted to evaluate the risks of total CVD, coronary heart disease (CHD), and stroke associated with cheese consumption.

Methods

Potentially eligible studies were identified by searching PubMed and EMBASE databases and by carefully reviewing the bibliographies of retrieved publications and related reviews. The summary relative risks (RRs) with 95 % confidence intervals (CIs) were calculated using the random-effects model.

Results

The final analyses included 15 prospective studies. Most of the studies excluded prevalent CVD at baseline (14/15) and had a duration >10 years (13/15). The summary RR for high vs. low cheese consumption was 0.90 (95 % CI 0.82–0.99) for total CVD (7 studies, 8076 events), 0.86 (95 % CI 0.77–0.96) for CHD (8 studies, 7631 events), and 0.90 (95 % CI 0.84–0.97) for stroke (7 studies, 10,449 events), respectively. The restricted cubic model indicated evidence of nonlinear relationships between cheese consumption and risks of total CVD (P _nonlinearity < 0.001) and stroke (P _nonlinearity = 0.015), with the largest risk reductions observed at the consumption of approximately 40 g/d.

Conclusions

This meta-analysis of prospective studies suggests a nonlinear inverse association between cheese consumption and risk of CVD.

     

Egg consumption and risk of GI neoplasms: dose–response meta-analysis and systematic review

Purpose

Previous epidemiological studies on egg consumption and the risk of gastrointestinal (GI) neoplasms suggest a positive association; however, data are limited and the evidence remains controversial. This study aims to investigate and quantify the potential dose–response relationship with an evaluation of cancer site-specific differences.

Methods

Relevant studies were identified after the literature search via electronic databases until January 2014. Subgroup analysis for serving portions was performed using two standardized classification methods: (1) less than 3, or 3 or more eggs per week; (2) less than 3, 3–5, or more than 5 eggs per week. Method two excludes studies that only reported consumption frequency. Pooled adjusted odds ratios (ORs) comparing highest and lowest categories of dietary pattern scores were calculated using a random-effects model.

Results

Thirty-seven case–control and seven cohort studies were included for meta-analysis, which contained a total of 424,867 participants and 18,852 GI neoplasm cases. The combined odds ratio (OR) was calculated to 1.15 (95 % CI 1.09–1.22; p value heterogeneity <0.001), showing only a slight increase in risk. The correlation was stronger for colon cancers 1.29 (95 % CI 1.14–1.46; p value heterogeneity <0.22). Dose–response analysis revealed similar results with stratification methods, and the ORs for an intake of <3 and ≥3 eggs per week were 1.14 (95 % CI 1.07–1.22; p value heterogeneity = 0.38) and 1.25 (95 % CI 1.14–1.38; p value heterogeneity = 0.25), respectively. With method 2, the ORs for an intake of <3, 3–5, and >5 eggs per week were 1.13 (95 % CI 1.06–1.21; p value heterogeneity = 0.25), 1.14 (95 % CI 1.01–1.29; p value heterogeneity = 0.06), and 1.19 (95 % CI 1.01–1.39; p value heterogeneity <0.001), respectively.

Conclusion

This study provides evidence that egg consumption is associated with a positive dose–response association with the development of GI neoplasms.     

Lack of association between occupational exposure to diesel exhaust and risk of pancreatic cancer: a systematic evaluation of available data

Purpose

To review epidemiologic studies on risk of pancreatic cancer and occupational exposure to diesel exhaust.

Methods

A literature search was conducted, and data were abstracted in a systematic fashion. Comparable results were combined using a random-effects meta-analysis.

Results

Twenty-six studies were included in the review, including five studies based on routine statistics, 11 case–control studies [meta-relative risk (RR) of three estimates for diesel exhaust exposure 0.9; 95 % confidence interval (CI) 0.5, 1.6] and ten cohort studies (meta-RR of their results: 1.03; 95 % CI 0.93, 1.13). Few studies reported results according to duration of exposure or other quantitative measures; no consistent pattern emerged.

Conclusions

The overall evidence from studies on occupational exposure to diesel exhaust and risk of pancreatic cancer leads to the conclusion of the absence of such association.     

Height and body fatness and colorectal cancer risk: an update of the WCRF–AICR systematic review of published prospective studies

Purpose

There is no published dose–response meta-analysis on the association between height and colorectal cancer risk (CRC) by sex and anatomical sub-site. We conducted a meta-analysis of prospective studies on the association between height and CRC risk with subgroup analysis and updated evidence on the association between body fatness and CRC risk.

Methods

PubMed and several other databases were searched up to November 2016. A random effects model was used to calculate dose–response summary relative risks (RR’s).

Results

47 studies were included in the meta-analyses including 50,936 cases among 7,393,510 participants. The findings support the existing evidence regarding a positive association of height, general and abdominal body fatness and CRC risk. The summary RR were 1.04 [95% (CI)1.02–1.05, I² = 91%] per 5 cm increase in height, 1.02 [95% (CI)1.01–1.02, I² = 0%] per 5 kg increase in weight, 1.06 [95% (CI)1.04–1.07, I² = 83%] per 5 kg/m² increase in BMI, 1.02 [95% (CI)1.02–1.03, I² = 4%] per 10 cm increase in waist circumference, 1.03 [95% (CI)1.01–1.05, I² = 16%] per 0.1 unit increase in waist to hip ratio. The significant association for height and CRC risk was similar in men and women. The significant association for BMI and CRC risk was stronger in men than in women.

Conclusion

The positive association between height and risk of CRC suggests that life factors during childhood and early adulthood might play a role in CRC aetiology. Higher general and abdominal body fatness during adulthood are risk factors of CRC and these associations are stronger in men than in women.

     

Physical activity and the risk of gestational diabetes mellitus: a systematic review and dose–response meta-analysis of epidemiological studies

Physical activity has been inconsistently associated with risk of gestational diabetes mellitus in epidemiological studies, and questions remain about the strength and shape of the dose–response relationship between the two. We therefore conducted a systematic review and meta-analysis of cohort studies and randomized trials on physical activity and gestational diabetes mellitus. PubMed, Embase and Ovid databases were searched for cohort studies, and randomized controlled trials of physical activity and risk of gestational diabetes mellitus, up to August 5th 2015. Summary relative risks (RRs) were estimated using a random effects model. Twenty-five studies (26 publications) were included. For total physical activity the summary RR for high versus low activity was 0.62 (95 % CI 0.41–0.94, I² = 0 %, n = 4) before pregnancy, and 0.66 (95 % CI 0.36–1.21, I² = 0 %, n = 3) during pregnancy. For leisure-time physical activity the respective summary RRs for high versus low activity was 0.78 (95 % CI 0.61–1.00, I² = 47 %, n = 8) before pregnancy, and it was 0.80 (95 % CI 0.64–1.00, I² = 17 %, n = 17) during pregnancy. The summary RR for pre-pregnancy activity was 0.70 (95 % CI 0.49–1.01, I² = 72.6 %, n = 3) per increment of 5 h/week and for activity during pregnancy was 0.98 (95 % CI 0.87–1.09, I² = 0 %, n = 3) per 5 h/week. There was evidence of a nonlinear association between physical activity before pregnancy and the risk of gestational diabetes mellitus, p_nonlinearity = 0.005, with a slightly steeper association at lower levels of activity although further reductions in risk were observed up to 10 h/week. There was also evidence of nonlinearity for physical activity in early pregnancy, p_nonlinearity = 0.008, with no further reduction in risk above 8 h/week. There was some indication of inverse associations between walking (before and during pregnancy) and vigorous activity (before pregnancy) and the risk of gestational diabetes mellitus. This meta-analysis suggests that there is a significant inverse association between physical activity before pregnancy and in early pregnancy and the risk of gestational diabetes mellitus. Further studies are needed to clarify the association between specific types and intensities of activity and gestational diabetes mellitus.     

Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials

Purpose

Although previous literature has reported that regular green tea consumption may improve blood pressure, the evidence from these studies is not consistent. The present study systematically reviewed randomised controlled trials and examined the effect of green tea consumption on blood pressure using meta-analysis.

Methods

Search of ProQuest, PubMed, Scopus and Cochrane Library (CENTERAL) was conducted, to identify eligible articles. Articles from 1995 to 2013 were included. A random-effect model was chosen to calculate the effect of combined trials.

Result

Thirteen studies were included in the meta-analysis. Green tea consumption significantly changed systolic blood pressure, by ?2.08 mm Hg (95 % CI ?3.06, ?1.05), and diastolic blood pressure, by ?1.71 mm Hg (95 % CI ?2.86, ?0.56), compared to the control. Changes in lipid profile, blood glucose and body mass index were also assessed in the meta-analysis. A significant reduction was found in total cholesterol (?0.15 mmol/L [95 % CI ?0.27, ?0.02]) and low-density lipoprotein cholesterol (?0.16 mmol/L [95 % CI ?0.22, ?0.09]). Changes in other parameters did not reach statistical significance. Subgroup analysis suggested a greater reduction in both systolic and diastolic blood pressure in studies that included participants with a baseline mean systolic blood pressure of ≥130 mm Hg, and studies involving consuming green tea as an extract.

Conclusion

The present meta-analysis suggests that green tea and its catechins may improve blood pressure, and the effect may be greater in those with systolic blood pressure ≥130 mm Hg. The meta-analysis also suggests that green tea catechins may improve total and low-density lipoprotein cholesterol.     

Is heme iron intake associated with risk of coronary heart disease? A meta-analysis of prospective studies

Purpose

Heme iron may contribute to the development of atherosclerosis by catalyzing production of hydroxyl-free radicals and promoting low-density lipoprotein oxidation. However, epidemiologic findings regarding the association between heme iron intake and risk of coronary heart disease (CHD) are inconsistent. We aimed to investigate the association by carrying out a meta-analysis of prospective studies.

Methods

Relevant studies were identified by using PubMed and EMBASE databases between January 1966 and April 2013 and also by manually reviewing the reference lists of retrieved publications. Summary relative risks (RRs) with corresponding 95 % confidence intervals (CIs) were computed using a random-effects model.

Results

Six prospective studies, which contained a total of 131,553 participants and 2,459 CHD cases, met the inclusion criteria. Combined results indicated that participants with higher heme iron intake had a 31 % increased risk of CHD, compared with those with lower intake (RR = 1.31, 95 % CI 1.04–1.67), with significant heterogeneity (P ^{heterogeneity} = 0.05, I ² = 55.0 %). Excluding the only study from Japan (limiting to Western studies) yielded a RR of 1.46 (95 % CI 1.21–1.76), with no study heterogeneity (P ^{heterogeneity} = 0.44, I ² = 0.0 %). The dose–response RR of CHD for an increase in heme iron intake of 1 mg/day was 1.27 (95 % CI 1.10–1.47), with low heterogeneity (P ^{heterogeneity} = 0.25, I ² = 25.8 %). We observed no significant publication bias.

Conclusions

This meta-analysis suggests that heme iron intake was associated with an increased risk of CHD.     

Coffee,tea, caffeine,and risk of hypertension: The Singapore Chinese Health Study

Purpose

The relationship between coffee and tea, and risk of hypertension remains controversial in Western populations. We investigated these associations in an Asian population.

Methods

The Singapore Chinese Health Study is a population-based prospective cohort that recruited 63,257 Chinese aged 45–74 years and residing in Singapore from 1993 to 1998. Information on consumption of coffee, tea, and other lifestyle factors was collected at baseline, and self-reported physician-diagnosed hypertension was assessed during two follow-up interviews (1999–2004, 2006–2010).

Results

We identified 13,658 cases of incident hypertension after average 9.5 years. Compared to those who drank one cup of coffee/day, the hazard ratios (HR) and 95% confidence intervals (CI) were 0.87 (0.83–0.91) for <weekly drinkers and 0.93 (0.86–1.00) for ≥3 cups/day drinkers. Compared to <weekly drinkers, daily drinkers of black or green tea had slight increase in risk, but these risk estimates were attenuated and became non-significant after adjustment for caffeine. After adjusting for coffee, there was a stepwise dose–response relationship between caffeine intake and hypertension risk; compared to the lowest intake (<50 mg/day), those in the highest intake (≥300 mg/day) had a 16% increase in risk; HR 1.16, 95% CI 1.04–1.31 (p trend?=?0.02).

Conclusions

Drinking coffee <1 cup/week or ≥3 cups/day had lower risk than drinking one cup/day. Caffeine may account for increased risk in daily tea drinkers and in those who drank one cup of coffee/day. The inverse U-shaped association with coffee suggests that at higher doses, other ingredients in coffee may offset the effect of caffeine and confer benefit on blood pressure.

     

Pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion

Purpose

To investigate the relation between pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion (SAB).

Methods

Our prospective cohort study included 15,590 pregnancies from 11,072 women with no history of SAB in the Nurses’ Health Study II (1991–2009). Beverage intake was assessed every 4 years using a validated questionnaire. Pregnancies were self-reported with case pregnancies lost spontaneously at <20 weeks gestation. Multivariable log-binomial regression models with generalized estimating equations were used to estimate the relative risks (RRs) and 95 % confidence intervals (CIs).

Results

There was a positive linear trend across categories of pre-pregnancy caffeine intake and risk of SAB such that women consuming >400 mg/day had 1.11 (95 % CI 0.98, 1.25) times the risk of SAB compared to women consuming <50 mg/day (p trend = 0.05). Total coffee intake had a positive, linear association with SAB. Compared to women with no pre-pregnancy coffee intake, women consuming ≥4 servings/day had a 20 % (6, 36 %) increased risk of SAB (p trend = 0.01). There was no difference in the association between caffeinated and decaffeinated coffee and risk of SAB. Pre-pregnancy intake of caffeinated tea, caffeinated soda, and decaffeinated soda had no association with SAB.

Conclusions

Pre-pregnancy coffee consumption at levels ≥4 servings/day is associated with increased risk of SAB, particularly at weeks 8–19.

     

Body mass index and physical activity and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies

Purpose

We conducted a systematic review and meta-analysis of prospective studies of the association between body mass index (BMI) and physical activity and diverticular disease risk.

Methods

PubMed and Embase databases were searched up to February 7, 2017. Summary relative risks and 95% confidence intervals (95% CIs) were calculated using a random effects model and nonlinear associations were modeled using fractional polynomial models.

Results

Six cohort studies of BMI and diverticular disease risk (28,915 cases, 1,636,777 participants) and five cohort studies of physical activity and diverticular disease risk (2080 cases, 147,869 participants) were included. The summary relative risk (RR) of incident diverticular disease for a 5 unit BMI increment was 1.28 (95% CI: 1.18–1.40, I ²?=?77%, n?=?6) for diverticular disease, 1.31 (95% CI: 1.09–1.56, I ²?=?74%, n?=?2) for diverticulitis, and 1.20 (95% CI: 1.04–1.40, I ²?=?56%, n?=?3) for diverticular disease complications. There was no evidence of a nonlinear association between BMI and diverticular disease risk (p _nonlinearity?=?0.22), and risk increased even within the normal weight range. Compared to a BMI of 20, the summary RR for a BMI of 22.5, 25.0, 27.5, 30.0, 32.5, 35.0, 37.5, and 40.0 was 1.15 (1.07–1.23), 1.31 (1.17–1.47), 1.50 (1.31–1.71), 1.71 (1.52–1.94), 1.96 (1.77–2.18), 2.26 (2.00–2.54), 2.60 (2.11–3.21), and 3.01 (2.06–4.39), respectively. The summary RR was 0.76 (95% CI: 0.63–0.93, I ²?=?54%, n?=?5) for high vs. low physical activity and 0.74 (95% CI: 0.57–0.97, I ²?=?39.5%, p _{heterogeneity}?=?0.20, n = 2) for high vs. low vigorous physical activity.

Conclusions

These results suggest that even moderate increases in BMI may increase the risk of diverticular disease as well as diverticular disease complications and that a higher level of physical activity may reduce the risk.

     

Circadian disrupting exposures and breast cancer risk: a meta-analysis

Purpose

Shift work, short sleep duration, employment as a flight attendant, and exposure to light at night, all potential causes of circadian disruption, have been inconsistently associated with breast cancer (BrCA) risk. The aim of this meta-analysis is to quantitatively evaluate the combined and independent effects of exposure to different sources of circadian disruption on BrCA risk in women.

Methods

Relevant studies published through January 2014 were identified by searching the PubMed database. The pooled relative risks (RRs) and corresponding 95 % confidence intervals (CIs) were estimated using fixed- or random effects models as indicated by heterogeneity tests. Generalized least squares trend test was used to assess dose–response relationships.

Results

A total of 28 studies, 15 on shift work, 7 on short sleep duration, 3 on flight attendants, and 6 on light at night were included in the analysis. The combined analysis suggested a significantly positive association between circadian disruption and BrCA risk (RR = 1.14; 95 % CI 1.08–1.21). Separate analyses showed that the RR for BrCA was 1.19 (95 % CI 1.08–1.32) for shift work, 1.120 (95 % CI 1.119–1.121) for exposure to light at night, 1.56 (95 % CI 1.10–2.21) for employment as a flight attendant, and 0.96 (95 % CI 0.86–1.06) for short sleep duration. A dose–response analysis showed that each 10-year increment of shift work was associated with 16 % higher risk of BrCA (95 % CI 1.06–1.27) based on selected case–control studies. No significant dose–response effects of exposure to light at night and sleep deficiency were found on BrCA risk.

Conclusions

Our meta-analysis demonstrates that circadian disruption is associated with an increased BrCA risk in women. This association varied by specific sources of circadian disrupting exposures, and a dose–response relationship remains uncertain. Therefore, future rigorous prospective studies are needed to confirm these relationships.

     

Prevalence of anemia and associated factors in women of childbearing age in rural Lebanon

Aim

This community-based, cross-sectional survey was conducted to determine the prevalence of anemia and iron deficiency anemia (IDA) and their association with nutritional behavior and other determinants.

Subjects and methods

Arabic-speaking women, aged 15–49 years old, residing in Lebanon’s rural areas were included. Demographic and behavioral characteristics, obstetrical and gynecological history, personal and family medical history, and dietary intake data were collected. Predictors of anemia and IDA were determined using logistic regression.

Results

A total of 578 women were included (Lebanese: 55.2%; Syrian: 43.3%) in which 35.5% had anemia and 23.2% had IDA. The mean number of pregnancies was 3.1 ± 3.0 (number of children: 2.5 ± 2.5). In total, 30% had a personal history of anemia or IDA, 29% a family history of anemia, and 20% a family history of IDA. Iron-rich products were consumed by >?90% of the women, whereby >?66.7% mentioned eating liver, tuna, dates and nuts. Syrian nationality (OR = 2.21; CI 95%: 1.38–3.54), age (OR = 1.03, CI 95%: 1.00–1.06), personal history of anemia (OR = 1.97; CI 95%: 1.31–2.95), consumption of dates (OR = 2.07, CI 95%: 1.29–3.31), molasses (OR = 1.61; CI 95%: 1.03–2.51), and soft drinks >?5 times/week (OR = 1.66; CI 95%: 1.09–2.53) were predictors of anemia. Syrian nationality (OR = 1.73, CI 95%: 1.14–2.62), number of pregnancies (OR = 1.08; CI 95%: 1.01–1.15), period >?8 days (OR = 2.01, CI 95%: 1.07–3.80), consumption of eggs (OR = 0.48; CI 95%: 0.25–0.90), dates (OR = 2.58, CI 95%: 1.49–4.46), and coffee or tea (OR = 1.59, CI 95%: 1.03–2.45) were predictors of IDA.

Conclusion

Anemia and IDA are prevalent in women of childbearing age in rural Lebanon. Intervention programs for raising the population’s awareness about IDA’s risk factors and proper nutrition must be implemented.

     

Musculoskeletal symptoms and psychosocial work environment,among Swedish commercial pilots

Purpose

The associations between psychosocial work conditions and health in pilots are understudied, and therefore, the associations between the psychosocial work conditions and musculoskeletal problems among Swedish commercial pilots were investigated.

Methods

In 2010, a self-administered questionnaire study was performed among pilots in one Swedish commercial airline: 354 pilots participated (61 %). Musculoskeletal symptoms and the psychosocial work conditions measured by the demand control social support model were investigated. Odds ratios (OR) with 95 % confidence interval (95 % CI) were expressed per change of one unit on the interquartile score scale.

Results

Pilots on long-haul flights had less elbow symptoms (OR 0.34, 95 % CI 0.14–0.85), and women had more hand symptoms (OR 2.90, 95 % CI 1.11–7.52). There were associations between high work demands and symptoms from the neck (OR 2.04, 95 % CI 1.45–2.88), shoulders (OR 1.46, 95 % 1.05–2.03), elbows (OR 1.79, 95 % CI 1.10–2.90) and low back (OR 1.42, 95 % CI 1.02–1.96) in pilots. Low social support was associated with symptoms from the neck (OR 1.87, 95 % 1.35–2.58), shoulders (OR 1.56, 95 % CI 1.14–2.14) and low back (OR 1.63, 95 % CI 1.18–2.24). Low supervisor support was associated with neck (OR 1.67, 95 % CI 1.22–2.27), shoulders (OR 1.38, 95 % CI 1.02–1.87) and low back symptoms (OR 1.48, 95 % CI 1.09–2.01). The associations were mainly found among first officers.

Conclusions

Musculoskeletal symptoms in pilots can be affected by poor psychosocial work conditions such as high demands and low social support, especially for first officers. The psychosocial aspects of organisational changes in commercial airlines should be taken into consideration.     

Shift work,long working hours and preterm birth: a systematic review and meta-analysis

Purpose

Specific physical activities or working conditions are suspected for increasing the risk of preterm birth (PTB). The aim of this meta-analysis is to review and summarize the pre-existing evidence on the effect of shift work or long working hours on the risk of PTB.

Methods

We conducted a systematic search in MEDLINE and EMBASE (1990–2013) for observational and intervention studies with original data. We only included articles that met our specific criteria for language, exposure, outcome, data collection and original data that were of at least of moderate quality. The data of the included studies were pooled.

Results

Eight high-quality studies and eight moderate-quality studies were included in the meta-analysis. In these studies, no clear or statistically significant relationship between shift work and PTB was found. The summary estimate OR for performing shift work during pregnancy and the risk of PTB were 1.04 (95 % CI 0.90–1.20). For long working hours during pregnancy, the summary estimate OR was 1.25 (95 % CI 1.01–1.54), indicating a marginally statistically significant relationship but an only slightly elevated risk.

Conclusion

Although in many of the included studies a positive association between long working hours and PTB was seen this did reach only marginal statistical significance. In the studies included in this review, working in shifts or in night shifts during pregnancy was not significantly associated with an increased risk for PTB. For both risk factors, due to the lack of high-quality studies focusing on the risks per trimester, in particular the third trimester, a firm conclusion about an association cannot be stated.     

Fatal child maltreatment associated with multiple births in Japan: nationwide data between July 2003 and March 2011

Objectives

The purpose of the present study is to clarify the impact of multiple births in fatal child maltreatment (child death due to maltreatment).

Methods

The national annual reports on fatal child maltreatment, which contain all cases from July 2003 to March 2011, published by the Ministry of Health, Labor and Welfare of Japan, were used as the initial sources of information. Parent–child murder–suicide cases were excluded from the analyses. Multiple births, teenage pregnancy and low-birthweight were regarded as the exposed groups. The relative risks (RRs) and their 95 % confidence intervals (CIs) were estimated using the data from the above reports and vital statistics. These analyses were performed both including and excluding missing values.

Results

Among 437 fatal child maltreatment cases, 14 multiple births from 13 families were identified. The RRs of multiple births per individual were 1.8 (95 % CI 1.0–3.0) when including missing values and 2.7 (95 % CI 1.5–4.8) when excluding missing values. The RRs of multiple births per family were 3.6 (95 % CI 2.1–6.2) when including missing values and 4.9 (95 % CI 2.7–9.0) when excluding missing values. The RR tended to be much lower than the RR of teenage pregnancy (RR 12.9 or 22.2), but slightly higher than the RR of low-birthweight (RR 1.4 or 2.9).

Conclusions

Families with multiple births had elevated risk for fatal child maltreatment both per individual and per family unit. Health providers should be aware that multiple pregnancies/births may place significant stress on families and should provide appropriate support and intervention.