Metformin use and survival after non‐small cell lung cancer: A cohort study in the US Military health system

Research suggests that metformin may be associated with improved survival in cancer patients with type II diabetes. This study assessed whether metformin use after non‐small cell lung cancer (NSCLC) diagnosis is associated with overall survival among type II diabetic patients with NSCLC in the U.S. military health system (MHS). The study included 636 diabetic patients with histologically confirmed NSCLC diagnosed between 2002 and 2007, identified from the linked database from the Department of Defense's Central Cancer Registry (CCR) and the Military Health System Data Repository (MDR). Time‐dependent multivariate Cox proportional hazards models were used to assess the association between metformin use and overall survival during follow‐up. Among the 636 patients, 411 died during the follow‐up. The median follow‐up time was 14.6 months. Increased post‐diagnosis cumulative use (per 1 year of use) conferred a significant reduction in mortality (adjusted hazard ratio (HR) = 0.76; 95% CI = 0.65–0.88). Further analysis by duration of use revealed that compared to non‐users, the lowest risk reduction occurred among patients with the longest duration of use (i.e. use for more than 2 years) (HR = 0.19; 95% CI = 0.09–0.40). Finally, the reduced mortality was particularly observed only among patients who also used metformin before lung cancer diagnosis and among patients at early stage of diagnosis. Prolonged duration of metformin use in the study population was associated with improved survival, especially among early stage patients. Future research with a larger number of patients is warranted.     

Diabetes,metformin and incidence of and death from invasive cancer in postmenopausal women: Results from the women's health initiative

Findings from studies of metformin use with risk of cancer incidence and outcome provide mixed results; with few studies examined associations by recency of diabetes diagnosis or duration of medication use. Thus, in the Women's Health Initiative, we examined these associations and further explored whether associations differ by recency of diabetes and duration of metformin use. Cox regression models were used to estimate hazard ratios (HR) and their 95% confidence intervals. Diabetes was associated with higher risk of total invasive cancer (HR, 1.13; p < 0.001) and of several site‐specific cancers (HR, 1.2–1.4, and up to over twofold). Diabetes was also associated with higher risk of death from cancer (HR, 1.46; p < 0.001). There was no overall difference in cancer incidence by diabetes therapy (p = 0.66). However, there was a lower risk of death from cancer for metformin users, compared to users of other medications, relative to women without diabetes, overall (HRs, 1.08 vs. 1.45; p = 0.007) and for breast cancer (HRs, 0.50 vs. 1.29; p = 0.05). Results also suggested that lower cancer risk associated with metformin may be evident only for a longer duration of use in certain cancer sites or subgroup populations. We provide further evidence that postmenopausal women with diabetes are at higher risk of invasive cancer and cancer death. Metformin users, particularly long‐term users, may be at lower risk of developing certain cancers and dying from cancer, compared to users of other anti‐diabetes medications. Future studies are needed to determine the long‐term effect of metformin in cancer risk and survival from cancer.     

Metformin and other anti-diabetic medication use and breast cancer incidence in the Nurses' Health Studies

We aimed to examine the association between the use of metformin and other anti-diabetic medications and breast cancer incidence within two large prospective cohort studies. We followed 185,181 women who participated in the Nurses' Health Study (NHS; 1994–2016) and the NHSII (1995–2017), with baseline corresponding to the date metformin was approved for type 2 diabetes (T2D) treatment in the US Information on T2D diagnosis, anti-diabetes medications, and other covariates was self-reported at baseline and repeatedly assessed by follow-up questionnaires every 2 years. Breast cancer cases were self-reported and confirmed by medical record review. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between medication use and breast cancer were estimated using Cox proportional hazards regression models, adjusting for breast cancer risk factors. During 3,324,881 person-years of follow-up, we ascertained 9,192 incident invasive breast cancer cases, of which 451 were among women with T2D. Compared with women without T2D (n = 169,263), neither metformin use (HR = 0.97; 95% CI = 0.81–1.15) nor other anti-diabetic medications use (HR = 1.11; 95% CI = 0.90–1.36) associated with significantly lower breast cancer incidence. Among women with T2D (n = 15,918), compared with metformin never users, metformin ever use was not significantly inversely associated with breast cancer (HR = 0.92; 95% CI = 0.74–1.15). Although we observed that past use of metformin was inversely associated with breast cancer in the T2D population (HR = 0.67; 95% CI = 0.48–0.94), current use (HR = 1.01; 95% CI = 0.80–1.27) and longer duration of metformin use were not associated with breast cancer (each 2-year interval: HR = 1.01; 95% CI = 0.95–1.07). Overall, metformin use was not associated with the risk of developing breast cancer among the overall cohort population or among women with T2D.     

Prospective study of Type 2 diabetes mellitus,anti‐diabetic drugs and risk of prostate cancer

Type 2 diabetes mellitus (T2DM) has consistently been associated with decreased risk of prostate cancer; however, if this decrease is related to the use of anti‐diabetic drugs is unknown. We prospectively studied men in the comparison cohort in the Prostate Cancer data Base Sweden 3.0, with data on T2DM, use of metformin, sulfonylurea and insulin retrieved from national health care registers and demographic databases. Cox proportional hazards regression models were used to compute hazard ratios (HR) and 95% confidence intervals (CI) of prostate cancer, adjusted for confounders. The study consisted of 612,846 men, mean age 72 years (standard deviation; SD = 9 years), out of whom 25,882 men were diagnosed with prostate cancer during follow up, mean time of 5 years (SD = 3 years). Men with more than 1 year's duration of T2DM had a decreased risk of prostate cancer compared to men without T2DM (HR = 0.85, 95% CI = 0.82–0.88) but among men with T2DM, those on metformin had no decrease (HR = 0.96, 95% CI = 0.77–1.19), whereas men on insulin (89%) or sulfonylurea (11%) had a decreased risk (HR = 0.73, 95% CI = 0.55–0.98), compared to men with T2DM not on anti‐diabetic drugs. Men with less than 1 year's duration of T2DM had no decrease in prostate cancer risk (HR = 1.11, 95% CI = 0.95–1.31). Our results gave no support to the hypothesis that metformin protects against prostate cancer as recently proposed. However, our data gave some support to an inverse association between T2DM severity and prostate cancer risk.     

Incident cancer risk after the start of aspirin use: Results from a Dutch population‐based cohort study of low dose aspirin users

Observational and intervention studies suggest that low dose aspirin use may prevent cancer. The objective of this study was to investigate the protective effect of long term low dose aspirin use (≤100 mg daily) on cancer in general and site‐specific cancer among low dose aspirin users in the Dutch general population. We conducted a population‐based cohort study with detailed information on aspirin exposure and cancer incidence. Only incident (new) low dose aspirin users, who were included in the linkage between PHARMO and the Eindhoven Cancer Registry (1998–2010) and free of cancer before the start of follow up were included. A Cox proportional hazard model with cumulative aspirin use as a time‐varying determinant was used to obtain hazard ratios (HR). Duration of aspirin use amongst 109,276 incident low dose aspirin users was not associated with a decreased risk of any of the site‐specific cancers or cancer in general (adjusted HR per year of aspirin use for all cancers: 1.02, 95% confidence interval [CI] 1.00–1.04, HR of >6 years aspirin use compared to <2 years: 1.17, 95% CI 1.02–1.34). After adjusting for current and past aspirin use, 2–6 years of low dose aspirin use was associated with a reduced colorectal cancer risk compared to <2 years of aspirin use (adjusted HR 0.75, 95% CI 0.59–0.96). However, a clear dose‐response relationship was not observed (adjusted HR >6 years aspirin use 0.95, 95% CI 0.60–1.49). Our results do not support the primary prevention of cancer among long term aspirin users.     

Neglected role of hookah and opium in gastric carcinogenesis: A cohort study on risk factors and attributable fractions

A recent study showed an association between hookah/opium use and gastric cancer but no study has investigated the relationship with gastric precancerous lesions. We examined the association between hookah/opium and gastric precancerous lesions and subsequent gastric cancer. In a population‐based cohort study, 928 randomly selected, healthy, Helicobacter pylori‐infected subjects in Ardabil Province, Iran, were followed for 10 years. The association between baseline precancerous lesions and lifestyle risk factors (including hookah/opium) was analyzed using logistic regression and presented as odds ratios (ORs) and 95% confidence intervals (CIs). We also calculated hazard ratios (HRs) and 95% CIs for the associations of lifestyle risk factors and endoscopic and histological parameters with incident gastric cancers using Cox regression models. Additionally, the proportion of cancers attributable to modifiable risk factors was calculated. During 9,096 person‐years of follow‐up, 36 new cases of gastric cancer were observed (incidence rate: 3.96/1,000 persons‐years). Opium consumption was strongly associated with baseline antral (OR: 3.2; 95% CI: 1.2–9.1) and body intestinal metaplasia (OR: 7.3; 95% CI: 2.5–21.5). Opium (HR: 3.2; 95% CI: 1.4–7.7), hookah (HR: 3.4; 95% CI: 1.7–7.1) and cigarette use (HR: 3.2; 95% CI: 1.4–7.5), as well as high salt intake, family history of gastric cancer, gastric ulcer and histological atrophic gastritis and intestinal metaplasia of body were associated with higher risk of gastric cancer. The fraction of cancers attributable jointly to high salt, low fruit intake, smoking (including hookah) and opium was 93% (95% CI: 83–98). Hookah and opium use are risk factors for gastric cancer as well as for precancerous lesions. Hookah, opium, cigarette and high salt intake are important modifiable risk factors in this high‐incidence gastric cancer area.     

Use of metformin and risk of kidney cancer in patients with type 2 diabetes

BackgroundThe anticancer effect of metformin has been reported in the literature but requires additional confirmation in epidemiologic studies. With respect to kidney cancer scarce data are available. This study investigates whether metformin use in patients with type 2 diabetes mellitus (T2DM) might affect kidney cancer risk.MethodsThe reimbursement database of the National Health Insurance in Taiwan was used. T2DM patients aged ≥40 years and newly treated with either metformin (n = 171,753, “ever users of metformin”) or other antidiabetic drugs (n = 75,499, “never users of metformin”) within 1998–2002 were followed for at least 6 months for kidney cancer until 31 December 2009. The treatment effect was estimated by Cox regression using propensity score weighting by inverse probability of treatment weighting approach. Hazard ratios were estimated for ever versus never users, and for tertiles of cumulative duration of metformin therapy.ResultsDuring follow-up, 917 ever users and 824 never users developed kidney cancer, with respective incidence of 80.09 and 190.30 per 100,000 person-years. The hazard ratio (95% confidence intervals) for ever versus never users is 0.279 (0.254–0.307); and is 0.598 (0.535–0.668), 0.279 (0.243–0.321) and 0.104 (0.088–0.124), respectively, for the first, second, and third tertile of cumulative duration of <14.5, 14.5–45.8 and >45.8 months. In subgroup analyses, the lower risk of kidney cancer associated with metformin use is consistently observed in both sexes, and in patients with or without concomitant use of other antidiabetic drugs.ConclusionMetformin use is associated with a decreased risk of kidney cancer in patients with T2DM.     

Non‐steroidal anti‐inflammatory drugs and cancer risk in women: Results from the Women's Health Initiative

The use of non‐steroidal anti‐inflammatory drugs (NSAIDs) has been associated with reduced risks of cancers at several sites in some studies; however, we recently reported no association between their use and total cancer risk in women in a prospective study. Here we examine the association between NSAIDs and total and site‐specific cancer incidence in the large, prospective Women's Health Initiative (WHI). Women (129,013) were recruited to participate in the WHI at 40 US clinical centers from 1993 to 1998 and followed prospectively. After 9.7 years of follow‐up, 12,998 incident, first primary, invasive cancers were diagnosed. NSAID use was systematically collected at study visits. We used Cox proportional hazards regression models to estimate multivariable‐adjusted hazard ratios (HR) and 95% confidence intervals (CI) for associations between NSAIDs use and total and site‐specific cancer risk. Relative to non‐use, consistent use (i.e., use at baseline and year 3 of follow‐up) of any NSAID was not associated with total cancer risk (HR 1.00, 95% CI: 0.94–1.06). Results for individual NSAIDs were similar to the aggregate measure. In site‐specific analyses, NSAIDs were associated with reduced risks of colorectal cancer, ovarian cancer, and melanoma. Our study confirms a chemopreventive benefit for colorectal cancer in women and gives preliminary evidence for a reduction of the risk of some rarer cancers. NSAIDs' benefit on cancer risk was therefore limited to specific sites and not evident when total cancer risk was examined. This information may be of importance when NSAIDs are considered as chemopreventive agents.     

Risk of prostate cancer in low‐dose aspirin users: A retrospective cohort study

A growing body of evidence indicates that use of low‐dose aspirin (LDA) reduces the risk of certain adenocarcinomas. While there are several and consistent findings on the protective effect of LDA on colorectal and other cancers, few and conflicting evidence is available on prostate cancer (PCa). The aim of this study was to assess whether LDA reduces the incidence rate of PCa. We conducted a nationwide, population‐based, retrospective cohort study by using Health Search IMS Health Longitudinal Patient Database (HSD). Patients with ischemic cardio‐ or cerebrovascular disease (index date) were identified. Time‐dependent multivariable Cox proportional hazard models were adopted to estimate Hazard Ratios (HRs) and related 95% confidence intervals (95% CI) of PCa associated with use of LDA. The exposure was lagged by one year to consider the latency of drug effect on the outcome onset. Within a cohort 13,453 patients, the overall incidence rate of PCa was 2.5 per 1,000 person‐years. Use of LDA was associated with a decreased incidence rate of PCa (HR = 0.64; 95% CI: 0.48–0.86), which was primarily driven by a frequency of LDA use equal to or higher than twice per week (HR = 0.60; 95% CI: 0.43–0.83). Such an association was more pronounced (HR = 0.43; 95% CI: 0.21–0.91) when LDA was used for five or more years. Our findings indicate that LDA use might be associated with a reduction of risk of PCa in patients with cardio‐ or cerebrovascular diseases.     

Metformin use among type 2 diabetics and risk of pancreatic cancer in a clinic‐based case–control study

A better understanding of the association between diabetes and pancreatic cancer (PC) may inform prevention and/or early detection strategies. Metformin has been associated with reduced risk of certain cancers, including PC, in some observational clinical studies. We assessed whether metformin use was associated with PC risk among those with type 2 diabetes (DM2), and whether metformin use modulated the association between DM2 and risk of PC. In total, 536 PC cases and 869 frequency‐matched controls were recruited predominantly from University of California San Francisco medical clinics from 2006 to 2011. Eligible participants completed direct interviews using a structured risk factor questionnaire. The association between metformin use and PC risk was assessed using propensity score‐weighted unconditional logistic regression methods in analyses restricted to diabetics and adjusted multivariable logistic models in the total study population. Ever use of metformin was not associated with PC risk in analyses restricted to DM2 (N = 170) participants (adjusted OR: 1.01, 95% CI: 0.61–1.68). In the total study population (N = 1,405) using nondiabetics as the referent group, PC risk was inversely associated with diabetes duration (p_trend < 0.001). Further, when DM2 participants were grouped by ever/never use of metformin and compared with nondiabetics, metformin use did not affect the association between DM2 and PC risk (never users: OR: 1.44, 95% CI: 0.78–2.67; ever users: OR: 1.19, 95% CI: 0.72–1.99). Results from our clinic‐based case–control study suggest that metformin use is not associated with PC risk among those with DM2 and does not alter the association between DM2 and PC risk.     

Reproductive factors,hormone use and gastric cancer risk: The Singapore Chinese Health Study

Gastric cancer incidence varies greatly worldwide, but is consistently twice as high in men than in women. The hormone‐related factors hypothesized to be associated with lower risk of gastric cancer in women have not been fully explored in populations with a high background risk of gastric cancer. The Singapore Chinese Health Study (SCHS) is a prospective cohort study in which 34,022 of the participants enrolled between 1993 and 1998 were women between 45 and 74 years of age. Information on reproductive histories, hormone replacement therapy (HRT) and oral contraceptive (OC) use was collected through in‐person interviews at baseline. As of December 31, 2013, 269 incident gastric cancer cases were identified. Multivariable‐adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate gastric cancer risk associations. Older age at natural menopause (≥55 versus <45 years: HR = 0.50, 95% CI: 0.25–0.99), type of menopause (other versus natural: HR = 0.48, 95% CI: 0.27–0.87) and greater years of menstrual cycling (fourth versus first quartile: HR = 0.67, 95% CI: 0.46–0.96) were associated with a decreased risk of gastric cancer. Ever use of OCs and HRT was also associated with reduced risk of gastric cancer; the multivariable‐adjusted HRs (95% CIs) were 0.40 (0.17–0.90) for use of HRT >3 years and 0.67 (0.47–0.94) for ever use of OCs, compared with never use. Reproductive factors associated with a longer window of fertility and the use of exogenous hormones were shown to reduce gastric cancer development in a cohort of Chinese women with a high background risk of gastric cancer.     

Contraceptive methods and ovarian cancer risk among Chinese women: A report from the Shanghai Women's Health Study

Oral contraceptive use is associated with reduced ovarian cancer risk; however, associations with other contraceptive methods, such as intrauterine device (IUD) and tubal ligation, are less clear. Women in China differ from western women in regard to mechanisms and duration of use of contraception. This study was undertaken to evaluate associations between contraceptive methods and ovarian cancer risk using data from the prospective Shanghai Women's Health Study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox proportional hazards regression. A total of 174 epithelial ovarian cancer cases were found to occur among 70,259 women who were followed‐up for a total of 888,258 person‐years. The majority of women had ever used any contraception (77.0%), including IUD (55.6%), oral contraceptive (20.4%), tubal ligation (14.7%) or contraceptive shots (2.6%). Ever use of any contraception was associated with a nonsignificant reduction in ovarian cancer risk (HR: 0.86, 95% CI: 0.60–1.24). Longer duration of IUD use was associated with lower ovarian cancer risk (p‐value for trend = 0.04). Compared with never users, women with durations of IUD use longer than the median (20 years) were 38% less likely to develop ovarian cancer (HR: 0.62, 95% CI: 0.40–0.97). Based on the high prevalence and long duration of IUD use among Chinese women, we estimate a preventive fraction of 9.3%, corresponding to approximately 16 ovarian cancer cases. High prevalence of long‐term IUD use may, therefore, contribute to the low incidence of ovarian cancer observed in China.     

Comparative safety of diabetes medications and risk of incident invasive breast cancer: a population-based cohort study

Purpose

Growing evidence suggests that certain commonly used diabetes medications have the potential to differentially alter breast cancer risk. We evaluated the influence of metformin, insulin, and sulfonylureas on risk of incident invasive breast cancer.

Methods

We conducted a retrospective cohort study of women ≥40 years of age enrolled in a health plan between 1996 and 2011. Ever, current (≤12 months), and duration (<1, 1–2.9, ≥3 years) of diabetes medication use were obtained from pharmacy databases and modeled as time varying. Multivariable Cox proportional hazards models adjusting for potential confounders including screening mammography and body mass index were used to estimate hazard ratios (HRs) and 95% Confidence Intervals (CIs).

Results

Among 10,050 women with diabetes, 57 % used metformin, 43 % used sulfonylureas, 32 % used insulin, and 301 were diagnosed with breast cancer over median follow-up of 6.7 years. Results suggested no significant decreased risk of breast cancer among metformin users (HR 0.86; 95% CI 0.65–1.12). We found no association between increased breast cancer risk and long-acting insulin (HR 0.95; 95% CI 0.51–1.77), but reduced risk with short-/rapid-acting insulin (HR 0.69; 95% CI 0.50–0.94), and suggestion of a dose–response with increasing duration of short-/rapid-acting insulin use (HR 0.87; 95% CI 0.76–1.00). Estimates for sulfonylurea users suggested increased risk with ever use (HR 1.18; 95% CI 0.90–1.53) and with longer durations of use (≥3 years: HR 1.23; 95% CI 0.88–1.73), but confidence intervals included 1.0.

Conclusions

Our results provide little support for the previously hypothesized decreased risk of breast cancer with metformin use or for an increased risk with insulin use. Implications for possible residual confounding by screening mammography and comorbidity should be considered in breast cancer pharmacoepidemiology studies.

     

Risk of high‐grade precancerous lesions and invasive cancers in high‐risk HPV‐positive women with normal cervix or CIN 1 at baseline—A population‐based cohort study

Infection with high‐risk human papillomavirus (HR‐HPV) is transient and clears on its own in majority of the women. Only a few women who have persistent infection may finally develop cervical intraepithelial neoplasia (CIN) or cervical cancer in later years. The risk of progression in the HR‐HPV‐positive women with normal cervix or low‐grade lesion on colposcopy and histopathology at baseline is less studied. We performed a longitudinal study on 650 HR‐HPV‐positive women with colposcopy and/or histopathology‐proved normal or CIN1 diagnosis at baseline to assess the cumulative risk of development of high‐grade CIN. After a mean follow‐up of 2.1 person years of observation (PYO) (range 0.1–5.1), the cumulative incidence of CIN2+ (6.4%; 3.0/100 PYO) was significantly higher in women who had persistent HR‐HPV infection compared to those who cleared the infection (adjusted HR 6.28; 95% CI 2.87–13.73). The risk of viral persistence in women aged 50–60 years was two times higher compared to women aged 40–49 years and three times higher compared to women aged 30–39 years. The probability of having persistent infection increased progressively with higher viral load at baseline (adjusted HR 3.29, 95% CI 2.21–4.90 for RLU ≥100; adjusted HR 2.69, 95% CI 1.71–4.22 for RLU 10–100). Women with increasing viral load at follow‐up had four times higher risk of developing CIN2 or worse lesions as compared to those with decreasing load (20.9% vs 4.8%; p < 0.001). In the context of developing countries where cytology or genotyping triaging is not feasible, colposcopy referral of HR‐HPV‐positive women with advancing age, viral persistence, and increasing viral load may be considered.     

Use of oral contraceptives,intrauterine devices and tubal sterilization and cancer risk in a large prospective study,from 1996 to 2006

The association of contraceptive methods, including oral contraceptives (OC), intrauterine devices (IUD) and tubal sterilization (TS), with overall and site‐specific cancer were prospectively investigated in a cohort of 66,661 Chinese women in Shanghai, 76.7% of whom used contraception. During a median follow‐up time of 7.5 years, 2,250 women were diagnosed with cancer. Ever‐use of any contraceptive method was not associated with overall cancer risk [adjusted hazard ratio (HR_adj) = 1.02, 95% CI, 0.92–1.12]. Use of any contraceptive method was associated with increased risk of rectal cancer (HR_adj = 1.68, 95% CI, 1.08–2.62) and reduced risk of thyroid cancer (HR_adj = 0.63, 95% CI, 0.38–1.04). Risk of gallbladder cancer increased with ever use of OC (HR_adj = 2.38, 95% CI, 1.26–4.49). IUD use was associated with a possible reduced risk of thyroid cancer (HR_adj = 0.64, 95% CI, 0.38–1.07). Longer duration of IUD use decreased risk for breast, thyroid and lung cancers. Ever having a TS was associated with increased uterine body cancer (HR_adj = 2.50, 95% CI, 1.47–4.25) and decreased risk of stomach cancer (HR_adj = 0.59, 95% CI, 0.39–0.91). We did not find any contraceptive method to be related to the risk of ovarian cancer but the analyses were based on few events. Although chance findings are a likely explanation for some of the associations found in our study, these findings suggest that various contraceptive methods or reproductive patterns may play a role in the etiology of cancer. © 2008 Wiley‐Liss, Inc.     

The occurrence of hepatocellular carcinoma in different risk stratifications of clinically noncirrhotic nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) may be a cause of hepatocellular carcinoma (HCC), but its high prevalence challenges current surveillance strategies. We aimed to evaluate HCC incidences in different risk stratifications for noncirrhotic NAFLD. Using Taiwan's National Health Insurance Research Database, we located 31,571 patients with NAFLD between the years 1998 and 2012. After excluding other causes of hepatitis, underlying cirrhosis or malignancy, 18,080 patients were recruited for final analysis. Cumulative incidences of HCC were analyzed after adjusting for competing mortality. With a median follow‐up duration of 6.32 years in the study cohort, the 10‐year cumulative incidence of HCC was 2.73% [95% confidence interval (CI): 1.69–3.76%]. Hepatoprotectant was used as a surrogate marker for elevated serum alanine transaminase (ALT). After adjusting for age, gender, hypertension, hypercholesterolemia, diabetes mellitus, gout, statin use, metformin use and aspirin use, elevated ALT was independently associated with an increased HCC risk [hazard ratio (HR) 6.80, 95% CI: 3.00–15.42; p < 0.001]. Multivariate stratified analysis verified this association in all subgroups (HR> 1.0). Moreover, increased age (HR 1.08 per year, 95% CI: 1.05–1.11) and statin use (HR 0.29, 95% CI: 0.12–0.68) were also identified as independent risk factors. The 10‐year cumulative HCC incidence was highest in older (age >55 years) patients with ALT elevation (12.41%, 95% CI: 5.99–18.83%), but lowest in younger patients without ALT elevation (0.36%, 95% CI: 0–1.08%). The incidence of HCC was relatively low in patients with clinically noncirrhotic NAFLD, however, HCC risk was significantly increased in older patients experiencing an elevated serum ALT.     

Association of Metformin,Other Antidiabetic Medications,and Statins With Incidence of Colon Cancer in Patients With Type 2 Diabetes

BackgroundMetformin and statins may have anticancer effects, with plausible cellular mechanisms. However, the association of these agents with the risk of colorectal cancer is unclear.Patients and MethodsThis was a retrospective cohort study on a large population (N = 316,317) of patients with type 2 diabetes. Data were obtained from the Diabetes in Finland database (FinDM). In a full cohort analysis, hazard ratios (HRs) with their 95% confidence intervals (CIs) for ever use versus never use were estimated using a multiple Poisson regression model. A nested case–control design within the cohort was used to examine the association of colon cancer (CC) with the defined daily dose of medication. The data were analyzed by conditional logistic regression. The analyses were adjusted for the patient’s age, sex, and duration of diabetes.ResultsIn total, 1351 CC cases were diagnosed during 1996-2011. The results revealed insufficient evidence for an association between metformin (HR, 1.01; 95% CI, 0.90-1.14), other oral antidiabetic medications (HR, 1.05; 95% CI, 0.93-1.19), insulin (HR, 1.02; 95% CI, 0.86-1.22), or statins (HR, 0.94; 95% CI, 0.84-1.05) and the incidence of CC in the full cohort analysis. The results from the case–control study were similar, with no consistent trend in the incidence of CC according to the cumulative dose of metformin or the other studied medications.ConclusionThis study found insufficient evidence for an association between metformin, insulin, other oral type 2 diabetes medications, or statins and the incidence of CC.     

Active cigarette smoking and risk of breast cancer

Although epidemiological evidence on the role of active cigarette smoking in breast cancer risk has been inconsistent, recent literature supports a modest association between smoking and breast cancer. This association is particularly observed in women who smoke for a long duration, or who smoke for a long time prior to their first pregnancy. Here, we provide updated results on cigarette smoking and breast cancer risk in the Canadian National Breast Screening Study (NBSS). The NBSS is a large cohort of 89,835 women, aged 40–59, who were followed for a mean of 22.1 years, resulting in the ascertainment of 6,549 incident cases of breast cancer. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of cigarette smoking variables with breast cancer risk. We found breast cancer to be associated with duration (40 years vs. 0: HR = 1.57; 95%CI = 1.29–1.92), intensity (40 cigarettes per day vs. 0: HR = 1.21; 95%CI = 1.04–1.40), cumulative exposure (40 pack‐years vs. 0: HR = 1.19; 95%CI = 1.06–1.13) and latency (40 years since initiation vs. 0: HR = 1.19; 95%CI = 1.10–1.53) of cigarette smoking. Number of years smoked prior to first full‐term pregnancy was associated with higher risk of breast cancer than comparative years smoked post‐pregnancy (among parous women, 5 years pre pregnancy vs. 0: HR = 1.18; 95%CI = 1.10–1.26). These results strongly support a role for cigarette smoking in breast cancer etiology and emphasize the importance of timing of this exposure.     

Diabetes mellitus and risk of cancer in Takayama: A population‐based prospective cohort study in Japan

Diabetes mellitus (DM) has been reported to be associated with an increased risk of site‐specific cancers; however, few studies have assessed associations of DM with both total and site‐specific cancers in Japan. We examined the association of a history of DM with cancer incidence in a population‐based prospective cohort study in Japan. A total of 14 173 men and 16 547 women over 35 years old, who completed a self‐administered baseline questionnaire in 1992, were followed up for cancer incidence from September 1992 to March 2008. At baseline, 6.3% men and 2.9% women had a history of diabetes. A total of 1974 men and 1514 women were identified as newly diagnosed with cancer. Hazard ratios (HR) and 95% confidence intervals (CI) were determined using Cox proportional hazards models. After controlling for potential confounders, men with DM had a modest risk increase of total cancer occurrence compared with those without DM (HR, 1.09; 95% CI, 0.93–1.29). Increased risk of cancer of the liver (HR, 2.18; 95% CI, 1.27–3.74), bile duct (HR, 2.17; 95% CI, 1.01–4.66), and larynx (HR, 3.61; 95% CI, 1.16–11.2) in diabetic men were observed. In women, significant increased risk of total cancer (HR, 1.35; 95% CI, 1.06–1.73) and stomach cancer (HR, 2.15; 95% CI, 1.30–3.54) were observed among diabetic subjects. These data suggest that people with DM may be at increased risk of both total and some site‐specific cancers.