Cigarette smoking and colorectal cancer incidence and mortality: Systematic review and meta‐analysis

The association between cigarette smoking and colorectal cancer (CRC) has been controversial. To synthesize the available data, we conducted a comprehensive meta‐analysis of all prospective studies. A total of 36 studies were included in our meta‐analysis. We examined the association between smoking and CRC, colon cancer and rectal cancer in terms of incidence and mortality. Separate analyses were conducted for smoking status, daily cigarette consumption, duration, pack‐years and age of initiation. Relative to nonsmokers, current and former smokers had a significantly increased risk of CRC incidence and mortality, respectively. When CRC data were combined with colon/rectal cancer data, current smokers had a significantly increased risk of CRC incidence. All 4 dose–response variables examined—daily cigarette consumption (RR = 1.38 for an increase of 40 cigarettes/day), duration (RR = 1.20 for an increase of 40 years of duration), pack‐years (RR = 1.51 for an increase of 60 pack‐years) and age of initiation (RR = 0.96 for a delay of 10 years in smoking initiation)—were significantly associated with CRC incidence (all p‐values < 0.0001). The relationship between duration of smoking and rectal cancer incidence was also significant. Among the subset of studies that distinguished cancer by site, a higher risk was seen for rectal cancer than for colon cancer for all analyses. Among prospective studies, a consistent association exists between smoking and CRC. The association is stronger for rectal cancer than for colon cancer in the subset of studies that differentiated cancer by site. © 2008 Wiley‐Liss, Inc.     

Sleep duration and breast cancer risk: A meta‐analysis of observational studies

Studies on the association of short or long sleep duration with breast cancer risk have reported inconsistent results. We quantitatively assessed this association by conducting a meta‐analysis based on the evidence from observational studies. In April 2013, we performed electronic searches in PubMed, EmBase and the Cochrane Library to identify studies examining the effect of sleep duration on breast cancer incidence. The odds ratio (OR) was used to measure any such association in a random‐effects model. The analysis was further stratified by confounding factors that could bias the results. A total of six studies (two case–control and four cohort studies) involving 159,837 individuals were included in our meta‐analysis. Our study did not show an association between either short or long sleep duration and breast cancer risk (short sleep duration data: pooled OR = 1.01, 95% confidence interval (CI) = 0.90–1.14, p = 0.853; long sleep duration data: pooled OR = 0.95, 95% CI = 0.86–1.04, p = 0.251). Moreover, we did not identify any statistically significant association between sleep duration and breast cancer risk in all the subgroup analyses. In conclusion, our findings indicate that sleep duration has no effect on breast cancer risk.     

Obesity and incidence of lung cancer: A meta‐analysis

To date, the relationship between obesity and the incidence of lung cancer remains unclear and inconclusive. Thus, we conducted a meta‐analysis of published studies to provide a quantitative evaluation of this association. Relevant studies were identified through PubMed and EMBASE databases from 1966 to December 2011, as well as through the reference lists of retrieved articles. A total of 31 articles were included in this meta‐analysis. Overall, excess body weight (body mass index, BMI ≥ 25 kg/m²) was inversely associated with lung cancer incidence (relative risk, RR = 0.79; 95% confidence interval, CI: 0.73–0.85) compared with normal weight (BMI = 18.5‐24.9 kg/m²). The association did not change with stratification by sex, study population, study design, and BMI measurement method. However, when stratified by smoking status, the inverse association between excess body weight and lung cancer incidence in current (RR = 0.63, 95% CI: 0.57–0.70) and former (RR = 0.73, 95% CI: 0.58–0.91) smokers was strengthened. In non‐smokers, the association was also statistically significant (RR = 0.83, 95% CI: 0.70–0.98), although the link was weakened to some extent. The stratified analyses also showed that excess body weight was inversely associated with squamous cell carcinoma (RR = 0.68, 95% CI: 0.58–0.80) and adenocarcinoma (RR = 0.79, 95% CI: 0.65–0.96). No statistically significant link was found between excess body weight and small cell carcinoma (RR = 0.99, 95% CI: 0.66–1.48). The results of this meta‐analysis indicate that overweight and obesity are protective factors against lung cancer, especially in current and former smokers.     

Association between physical activity and all cancer mortality: Dose–response meta‐analysis of cohort studies

The relationship between physical activity (PA) before cancer diagnosis and all cancer mortality among the general population is not well defined because of inconsistent results from published studies. Thus, the lack of a meta‐analysis that addresses that issue prompted the current report. We conducted a literature search of PubMed and Web of Science to identify all relevant epidemiological studies published before February 28, 2015. We performed categorical and dose–response meta‐analyses to evaluate and quantify the association between pre‐diagnosis PA and all cancer mortality. A total of 32 prospective cohort studies involving 59,362 cancer deaths were included in this meta‐analysis. The pooled relative risks (RRs) of all cancer mortality were 0.80 [95% confidence interval (CI) = 0.76–0.85)] for highest versus lowest PA group and 0.85 (95% CI = 0.82–0.88) for PA versus non/occasional PA group. Dose–response analysis showed that the increment in pre‐diagnosis PA level was associated with a decreased risk of cancer death continuously. Moreover, an increment of 10 MET‐h/week was related to a 7% lower risk for all cancer mortality (RR = 0.93, 95% CI = 0.91–0.95). In conclusion, the present meta‐analysis provides evidence of an inverse association between pre‐diagnosis PA and all cancer mortality among the general population. High‐quality epidemiological studies that employ standardized PA assessments and unified definitions of PA levels should be developed in future.     

Effects of statins on cancer mortality and progression: A systematic review and meta‐analysis of 95 cohorts including 1,111,407 individuals

Statins have been implicated in the regulation of cell proliferation, apoptosis and tumor progression in cancer patients and statin use at the time of cancer diagnosis has been reported to be associated with reduced cancer risk and improved survival, irrespective of concomitant anti‐cancer therapy. A systematic literature search of relevant databases through May 2015 was conducted to identify studies assessing the prognostic impact of statin use on prognostic outcomes in cancer patients. Literature search identified 95 cohort studies that met the inclusion criteria. A meta‐analysis of 55 articles showed that statin use was significantly associated with decreased risk of all‐cause mortality (HR 0.70, 95% Cl 0.66 to 0.74) compared with nonusers. The observed pooled estimates were retained for cancer‐specific mortality (HR 0.60, 95% Cl 0.47 to 0.77), progression‐free survival (HR 0.67, 95% Cl 0.56 to 0.81), recurrence‐free survial (HR 0.74, 95% Cl 0.65 to 0.83) and disease‐free survival (HR 0.53, 95% Cl 0.40 to 0.72). These associations almost remained consistent across those outcomes when stratified by publication type, tumour location, study design, sample size, initiation of statins, disease stage, research country, follow‐up duration or research hospital involved. Subgroup analyses according to initiation of statins showed postdiagnosis statin users (HR 0.65, 95% Cl 0.54 to 0.79) gained significantly more recurrence‐free survival benefit than prediagnosis statin users (HR 0.86, 95% Cl 0.77 to 0.96) (p for interaction = 0.018). Statin therapy has potential survival benefit for patients with malignancy. Further large‐scale prospective studies emphasising survival outcomes of individual cancer type are strongly encouraged.     

Hysterectomy and kidney cancer risk: A meta‐analysis

Recent cohort findings suggest that women who underwent a hysterectomy have an elevated relative risk of kidney cancer, although evidence from past studies has been inconsistent. We conducted a systematic review and meta‐analysis of published cohort and case–control studies to summarize the epidemiologic evidence investigating hysterectomy and kidney cancer. Studies published from 1950 through 2012 were identified through a search of PubMed and of references from relevant publications. Meta‐analyses were conducted using random‐effects models to estimate summary relative risks (SRRs) and 95% confidence intervals (CIs) for hysterectomy, age at hysterectomy (<45, 45+ years) and time since hysterectomy (<10, 10+ years). The SRR for hysterectomy and kidney cancer for all published studies (seven cohort, six case–control) was 1.29 (95% CI, 1.16–1.43), with no evidence of between‐study heterogeneity or publication bias. The summary effect was slightly weaker, although still significant, for cohorts (SRR, 1.26; 95% CI, 1.11–1.42) compared with case–control findings (1.37; 95% CI, 1.09–1.73) and was observed irrespective of age at hysterectomy, time since the procedure and model adjustment for body mass index, smoking status and hypertension. Women undergoing a hysterectomy have an approximate 30% increased relative risk of subsequent kidney cancer. Additional research is needed to elucidate the biological mechanisms underlying this association.     

Mindfulness‐based stress reduction and cancer: a meta‐analysis

Objective: This meta‐analysis was conducted to investigate the effects of mindfulness‐based stress reduction (MBSR) on the mental and physical health status of various cancer patients. Methods: Ten studies (randomized‐controlled trials and observational studies) were found to be eligible for meta‐analysis. Individual study results were categorized into mental and physical variables and Cohen's effect size d was computed for each category. Results: MBSR may indeed be helpful for the mental health of cancer patients (Cohen's effect size d=0.48); however, more research is needed to show convincing evidence of the effect on physical health (Cohen's effect size d=0.18). Conclusion: The results suggest that MBSR may improve cancer patients' psychosocial adjustment to their disease. Copyright © 2008 John Wiley & Sons, Ltd.     

Computed tomographic cephalometric analysis of Chinese patients with obstructive sleep apnoea

Variations of craniofacial and upper airway structures are recognized to contribute to the phenomenon of obstructive sleep apnoea (OSA). Most previous cephalometric studies were performed using erect lateral radiographs in Caucasian patients. The present project aims to determine cephalometric measurements, utilizing CT, in normal Chinese subjects and in Chinese patients with OSA. Computed tomography of 25 patients with OSA (proven using overnight polysomnography), and of 25 age‐, sex‐, height‐, bodyweight‐ and body mass index (BMI)‐matched control subjects were prospectively performed. Thirteen standard bony and soft‐tissue measurements were obtained from the CT lateral scout view of the head and neck, taken with each subject in the neutral supine position. The cross‐sectional area was calculated at two axial levels (velopharynx and hypopharynx). The measurements in the two groups, OSA and control subjects, were compared. The measurements for hyoid position (P = 0.00), nasal cavity length (P = 0.01), mandibular prognathism (P = 0.05), tongue size (P = 0.02), oropharyngeal airway space (P = 0.02), posterior tongue airway space (P = 0.04) and cross‐sectional areas at the level of the velopharynx (P = 0.00) and hypopharynx (P = 0.01) differed significantly between the two groups. In conclusion, CT cephalometric measurements show that certain anatomical variations in the head and neck are likely to contribute to the pathogenesis of OSA in Chinese patients.     

Genetic polymorphism of miR‐146a is associated with gastric cancer risk: a meta‐analysis

Several studies have investigated the associations between miR‐146a rs2910164 and gastric cancer (GC) risk, but results have been inconclusive. To derive a more precise estimation of the relationship, a meta‐analysis was performed. PubMed and China National Knowledge Infrastructure searches were carried out for relevant studies published before July 2014. Meta‐analysis was performed with the stata , version 11.0. A total of seven case–control studies, including 3283 cases and 4535 controls, were selected. A significant association was found between rs2910164 and GC risk under all genetic models (CC vs. GG, OR = 0.76, 95% CI = 0.66–0.87; CC vs. GC+GG, OR = 0.84, 95% CI = 0.71–0.99; CC+GC vs. GG, OR = 0.82, 95% CI = 0.73–0.91) for the total data. In the subgroup analysis by ethnicity, statistically significant association was found in Asian. This meta‐analysis suggested that the miR‐146a rs2910164 was a risk factor for developing GC.     

Impact of statin use on cancer recurrence and mortality in breast cancer: A systematic review and meta‐analysis

Statins have shown antineoplastic properties in preclinical studies with breast cancer cells. They inhibit the enzyme “HMG CoA reductase” and the expression of this enzyme in cancer cells has been implicated as a favorable prognostic factor in patients with breast cancer. After a search of MEDLINE and Embase from inception through November 2015, 817 abstracts were reviewed to identify studies that described an association between statin use and outcomes in breast cancer. A total of 14 studies which included 75,684 women were identified. In a meta‐analysis of 10 studies, statin use was associated with improved recurrence‐free survival (RFS; HR 0.64; 95% CI 0.53–0.79, I² = 44%). Furthermore, this RFS benefit appeared to be confined to use of lipophilic statins (HR 0.72; 95% CI 0.59–0.89) as hydrophilic statin use was not associated with improvement in RFS (HR 0.80; 95% CI 0.44–1.46). Statin users similarly showed improved overall survival in a meta‐analysis with substantial heterogeneity (8 studies, HR 0.66; 95% CI 0.44–0.99, I² = 89%). Statin users also had improved cancer‐specific survival, although this relationship was measured with less precision (six studies, HR 0.70; 95% CI 0.46–1.06, I² = 86%). In conclusion, breast cancer patients who use statins, or specifically, lipophilic statins show improved recurrence‐free survival. Statin users also had improved overall survival and cancer‐specific survival. These findings should be assessed in a prospective randomized cohort and the choice of statin, dose and biomarkers that may predict the efficacy of these drugs should be identified.     

Breast cancer incidence and mortality in a Caribbean population: comparisons with African-Americans

We describe breast cancer incidence and mortality in the predominantly African-origin population of Barbados, which shares an ancestral origin with African-Americans. Age-standardized incidence rates were calculated from histologically confirmed breast cancer cases identified during a 45-month period (July 2002-March 2006). Mortality rates were estimated from death registrations over 10-years starting January 1995. There were 396 incident cases of breast cancer for an incidence rate of 78.1 (95% confidence interval (CI) 70.5-86.3), standardized to the US population. Breast cancer incidence in African-Americans between 2000 and 2004 was 143.7 (142.0-145.5) per 100,000. Incidence peaked at 226.6 (174.5-289.4) per 100,000 among Barbadian women aged 50-54 years, and declined thereafter, a pattern in marked contrast to trends in African-American women, whose rates continued to increase to a peak of 483.5 per 100,000 in those aged 75-79 years. Incidence rate ratios comparing Barbadian and African-American women showed no statistically significant differences among women aged>or=55 years (p相似文献   

Alcohol drinking and pancreatic cancer risk: a meta‐analysis of the dose‐risk relation

In order to provide a more precise quantification of the association between alcohol consumption and pancreatic cancer risk, we performed a meta‐analysis of relevant dose‐risk results. We conducted a PubMed search of all case‐control (N=21) and cohort (N=11) studies published up to March 2009. We computed summary relative risk (RR) estimates using either fixed‐ or, in the presence of heterogeneity, random‐effects models. The pooled RR was 0.92 (95% confidence interval, 95% CI, 0.86–0.97) for <3 drinks/day and 1.22 (95% CI, 1.12–1.34) for ≥3 drinks/day. The increased risk for heavy drinking was similar in women and men, but apparently stronger in cohort studies (RR=1.29), in studies with high quality index (RR=1.30), and did not appear to be explained by residual confounding by either history of pancreatitis or tobacco smoking. This meta‐analysis provides strong evidence for the absence of a role of moderate drinking in pancreatic carcinogenesis, coupled to an increased risk for heavy alcohol drinking. Given the moderate increase in risk and the low prevalence of heavy drinkers in most populations, alcohol appears to be responsible only for a small fraction of all pancreatic cancers.     

Association between height and thyroid cancer risk: A meta‐analysis of prospective cohort studies

While several epidemiological studies have investigated the relationship between height and risk for thyroid cancer, the results were inconsistent. In the present study, a systematic review and meta‐analysis of prospective cohort studies was conducted to assess the impact of height on thyroid cancer risk. Online databases were searched up to December 30, 2014, for prospective cohort studies on the association between height and thyroid cancer risk. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random‐effects model of meta‐analysis. In all, 11 articles were included in this meta‐analysis, including 15 prospective cohort studies, containing 6,695,593 participants and 7,062 cases of thyroid cancer. By comparing the highest versus the lowest categories of height, we reported that risk of thyroid cancer was increased with height in both men (summary RR = 1.40, 95%CI 1.09–1.78, p = 0.008) and women (summary RR = 1.54, 95%CI 1.30–1.83, p < 0.001). The summary RR of thyroid cancer per 5‐cm increase in height was 1.16 (95%CI 1.09–1.23, p < 0.001). The results were similar among men (per 5‐cm increase RR = 1.13, 95%CI 1.03–1.23, p = 0.011) and women (per 5‐cm increase RR = 1.18, 95%CI 1.10–1.27, p < 0.001). No obvious risk of publication bias was observed. Our meta‐analysis provides strong evidence for a dose–response relationship between height and risk of thyroid cancer in both men and women.     

Cancer incidence and mortality: A cohort study in China, 2008–2013

The National Central Cancer Registry of China (NCCR) was the only available source of cancer monitoring in China, even though only about 70% of cancer registration sites were qualified by now. In this study, based on a national large prospective cohort‐the China Kadoorie Biobank (CKB), we aimed to provide additional cancer statistics and compare the difference of cancer burden between urban and rural areas of China. A total of 497,693 cancer‐free participants aged 35–74 years were recruited and successfully followed up from 2004 to 2013 in 5 urban and 5 rural areas across China. Except for traditional registration systems, the national health insurance system and active follow‐up were used to determine new cancer incidents and related deaths. The mortality‐to‐incidence ratio (MIR) was used to compare the differences of cancer burden between urban and rural areas of China. We found that cancer mortality coincided well between our cohort and NCCR, while the incidence was much higher in our cohort. Based on CKB, we found the MIR of all cancers was 0.54 in rural areas, which was approximately one‐third higher than that in urban areas with 0.39. Cancer profiles in urban areas were transiting to Western distributions, which were characterized with high incidences of breast cancer and colorectal cancer; while cancers of the esophagus, liver and cervix uteri were still common in rural areas of China. Our results provide additional cancer statistics of China and demonstrate the differences of cancer burden between urban and rural areas of China.     

Thyroid cancer mortality and incidence: A global overview

In most areas of the world, thyroid cancer incidence has been appreciably increasing over the last few decades, whereas mortality has steadily declined. We updated global trends in thyroid cancer mortality and incidence using official mortality data from the World Health Organization (1970–2012) and incidence data from the Cancer Incidence in Five Continents (1960–2007). Male mortality declined in all the major countries considered, with annual percent changes around ?2/?3% over the last decades. Only in the United States mortality declined up to the mid 1980s and increased thereafter. Similarly, in women mortality declined in most countries considered, with APCs around ?2/?5% over the last decades, with the exception of the UK, the United States and Australia, where mortality has been declining up to the late 1980s/late 1990s to level off (or increase) thereafter. In 2008–2012, most countries had mortality rates (age‐standardized, world population) between 0.20 and 0.40/100,000 men and 0.20 and 0.60/100,000 women, the highest rates being in Latvia, Hungary, the Republic of Moldova and Israel (over 0.40/100,000) for men and in Ecuador, Colombia and Israel (over 0.60/100,000) for women. In most countries, a steady increase in the incidence of thyroid cancer (mainly papillary carcinomas) was observed in both sexes. The declines in thyroid cancer mortality reflect both variations in risk factor exposure and changes in the diagnosis and treatment of the disease, while the increases in the incidence are likely due to the increase in the detection of this neoplasm over the last few decades.     

Use of benzodiazepine and risk of cancer: A meta‐analysis of observational studies

Several observational epidemiological studies have reported inconsistent results on the association between the use of benzodiazepine and the risk of cancer. We investigated the association by using a meta‐analysis. We searched PubMed, EMBASE, and the bibliographies of relevant articles to locate additional publications in January 2016. Three evaluators independently reviewed and selected eligible studies based on predetermined selection criteria. Of 796 articles meeting our initial criteria, a total of 22 observational epidemiological studies with 18 case‐control studies and 4 cohort studies were included in the final analysis. Benzodiazepine use was significantly associated with an increased risk of cancer (odds ratio [OR] or relative risk [RR] 1.19; 95% confidence interval 1.16–1.21) in a random‐effects meta‐analysis of all studies. Subgroup meta‐analyses by various factors such as study design, type of case‐control study, study region, and methodological quality of study showed consistent findings. Also, a significant dose‐response relationship was observed between the use of benzodiazepine and the risk of cancer (p for trend <0.01). The current meta‐analysis of observational epidemiological studies suggests that benzodiazepine use is associated with an increased risk of cancer.     

Gender differences in colorectal cancer survival: A meta‐analysis

A meta‐analysis was conducted to determine the influence of gender on overall survival (OS) and cancer‐specific survival (CSS) in colorectal cancer patients. Major databases were searched for clinical trials, which compare survival differences between male and female for colorectal cancer patients. A list of these studies and references, published in English and Chinese from 1960 to 2017, was obtained independently by two reviewers from databases such as PubMed, Medline, ScienceDirect, the China National Knowledge Infrastructure (CNKI) and Web of Science. Overall survival and cancer‐specific survival were compared using Review Manager 5.3. Females had significantly better OS (hazard ratio [HR] = 0.87; 95% confidence interval [CI] = 0.85–0.89) and CSS (HR = 0.92; 95% CI = 0.89–0.95) than males after meta‐analysis. These results suggest that gender seems to be a significant factor influencing survival results among colorectal cancer patients.     

Associations between statin use and non‐Hodgkin lymphoma (NHL) risk and survival: a meta‐analysis

Evidence on the effect of statin use on non‐Hodgkin lymphoma (NHL) is not clear. We conducted a systematic review and meta‐analysis to examine the associations between statin use and NHL risk and survival. We searched multiple literature sources up to October 2014 and identified 10 studies on the risk of diagnosis with NHL and 9 studies on survival. Random effects model was used to calculate pooled odds ratio (PORs) for risk and pooled hazard ratio (PHR) for survival. Heterogeneity among studies was examined using the Tau‐squared and the I‐squared (I²) tests. Statin use was associated with reduced risk for total NHL (POR = 0.82, 95% CI 0.69–0.99). Among statin users, there was a lower incidence risk for marginal zone lymphoma (POR = 0.54, 95% CI 0.31–0.94), but this was not observed for other types of NHL. However, statin use did not affect overall survival (PHR = 1.02, 95% CI 0.99–1.06) or event‐free survival (PHR = 0.99, 95% CI 0.87–1.12) in diffuse large B‐cell lymphoma. There is suggestive epidemiological evidence that statins decrease the risk of NHL, but they do not influence survival in NHL patients. Copyright © 2015 John Wiley & Sons, Ltd.