Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Department of Surgical and Perioperative Sciences, Urology and Andrology, Umeå University Hospital, Umeå, Sweden. Electronic address: email@example.com.
BACKGROUND: Prospective studies have indicated that elevated blood glucose levels may be linked with increased cancer risk, but the strength of the association is unclear. We examined the association between blood glucose and cancer risk in a prospective study of six European cohorts. METHODS AND FINDINGS: The Metabolic syndrome and Cancer project (Me-Can) includes cohorts from Norway, Austria, and Sweden; the current study included 274,126 men and 275,818 women. Mean age at baseline was 44.8 years and mean follow-up time was 10.4 years. Excluding the first year of follow-up, 18,621 men and 11,664 women were diagnosed with cancer, and 6,973 men and 3,088 women died of cancer. We used Cox regression models to calculate relative risk (RR) for glucose levels, and included adjustment for body mass index (BMI) and smoking status in the analyses. RRs were corrected for regression dilution ratio of glucose. RR (95% confidence interval) per 1 mmol/l increment of glucose for overall incident cancer was 1.05 (1.01-1.10) in men and 1.11 (1.05-1.16) in women, and corresponding RRs for fatal cancer were 1.15 (1.07-1.22) and 1.21 (1.11-1.33), respectively. Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri, and stomach. CONCLUSIONS: Data from our study indicate that abnormal glucose metabolism, independent of BMI, is associated with an increased risk of cancer overall and at several cancer sites. Our data showed stronger associations among women than among men, and for fatal cancer compared to incident cancer. Please see later in the article for the Editors' Summary.
Brain tumour has few established determinants. We assessed to which extent risk of brain tumour was related to metabolic syndrome factors in adults.
In the Me-Can project, 580?000 individuals from Sweden, Austria, and Norway were followed for a median of 10 years after baseline measurement. Data on brain tumours were obtained from national cancer registries. The factors of metabolic syndrome (BMI, SBP and DBP, and blood levels of glucose, cholesterol, and triglycerides), separately and combined, were analysed in quintiles and for transformed z-scores (mean transformed to 0 and standard deviation to 1). Cox proportional hazards multivariate regression models were used, with corrections for measurement error.
During follow-up, 1312 primary brain tumours were diagnosed, predominantly meningioma (n?=?348) and high-grade glioma (n?=?436). For meningioma, the hazard ratio was increased for z-scores of SBP [hazard ratio?=?1.27 per unit standard deviation, 95% confidence interval (CI) 1.03-1.57], of DBP (hazard ratio?=?1.29, 95% CI 1.04-1.58), and of the combined metabolic syndrome score (hazard ratio?=?1.31, 95% CI 1.11-1.54). An increased risk of high-grade glioma was found for DBP (hazard ratio?=?1.23, 95% CI 1.01-1.50) and triglycerides (hazard ratio?=?1.35, 95% CI 1.05-1.72). For both meningioma and high-grade glioma, the risk was more than double in the fifth quintiles of DBP compared to the lowest quintile. For meningioma this risk was even larger for SBP.
Increased blood pressure was associated with risk of brain tumours, especially of meningiomas.
Observational studies have shown inconsistent results for the association between blood pressure and cancer risk. We investigated the association in 7 cohorts from Norway, Austria, and Sweden. In total, 577799 adults with a mean age of 44 years were followed for, on average, 12 years. Incident cancers were 22184 in men and 14744 in women, and cancer deaths were 8724 and 4525, respectively. Cox regression was used to calculate hazard ratios of cancer per 10-mmHg increments of midblood pressure, which corresponded with 0.7 SDs and, for example, an increment of systolic/diastolic blood pressure of 130/80 to 142/88 mmHg. All of the models used age as the time scale and were adjusted for possible confounders, including body mass index and smoking status. In men, midblood pressure was positively related to total incident cancer (hazard ratio per 10 mmHg increment: 1.07 [95% CI: 1.04-1.09]) and to cancer of the oropharynx, colon, rectum, lung, bladder, kidney, malignant melanoma, and nonmelanoma skin cancer. In women, midblood pressure was not related to total incident cancer but was positively related to cancer of the liver, pancreas, cervix, uterine corpus, and malignant melanoma. A positive association was also found for cancer mortality, with HRs per 10-mmHg increment of 1.12 (95% CI: 1.08-1.15) for men and 1.06 (95% CI: 1.02-1.11) for women. These results suggest a small increased cancer risk overall in men with elevated blood pressure level and a higher risk for cancer death in men and women.
Comments to the letters by Per-Henrik Zahl and Jan Maehlen and by Peter C. Gotzsche concerning our article: Increased incidence of invasive breast cancer after the introduction of service screening with mammography in Sweden.
To evaluate a method for collecting data concerning low back pain (LBP) using daily text messages and to characterize the reported LBP in terms of intensity, variability, and episodes.
We conducted a cohort study of LBP among workers used by a mining company. The participants were asked to answer the question "How much pain have you had in your lower back in the last 24 hours on a scale from 0 to 10, where 0 = no pain and 10 = the worst pain imaginable" once a day for 5 weeks, with this process being repeated 6 months later.
A total of 121 workers participated in the first period of data collection, and 108 participated in the second period. The daily response rate was 93% for both periods, and cluster analysis was shown to be a feasible statistical method for clustering LBP into subgroups of low, medium, and high pain. The daily text messages method also worked well for assessing the episodic nature of LBP.
We have demonstrated a method for repeatedly measuring of LBP using daily text messages. The data permitted clustering into subgroups and could be used to define episodes of LBP.
The ratio (R) of prevalence of screening-detected breast cancer in the first screening round (P) was compared with the expected incidence rate (I) for different age groups in several screening programs. Published data on the first screening round from three Swedish randomized trials and six counties with service screening were used. The women invited to take part in the screening were aged 40-74 years. Not only P and I but also R increased with increasing age. With the youngest age group as reference, the increase was statistically significant for both invasive cancer and invasive cancer and carcinoma in situ together. The studied ratio (R) can be thought of as a measure of efficiency in detecting breast cancer cases in mammography screening. The reasons for the increase are probably that the breast tissue of younger women is denser, which makes the cancer more difficult to detect by mammography, and that slow-growing cancers tend to appear more frequently in older women.
The effectiveness of mammography screening for women ages 40 to 49 years still is questioned, and few studies of the effectiveness of service screening for this age group have been conducted.
Breast cancer mortality was compared between women who were invited to service screening at ages 40 to 49 years (study group) and women in the same age group who were not invited during 1986 to 2005 (control group). Together, these women comprise the Mammography Screening of Young Women (SCRY) cohort, which includes all Swedish counties. A prescreening period was defined to facilitate a comparison of mortality in the absence of screening. The outcome measure was refined mortality, ie, breast cancer death for women who were diagnosed during follow-up at ages 40 to 49 years. Relative risks (RRs) with 95% confidence intervals (CIs) were estimated.
There was no significant difference in breast cancer mortality during the prescreening period. During the study period, there were 803 breast cancer deaths in the study group (7.3 million person-years) and 1238 breast cancer deaths in the control group (8.8 million person-years). The average follow-up was 16 years. The estimated RR for women who were invited to screening was 0.74 (95% CI, 0.66-0.83), and the RR for women who attended screening was 0.71 (95% CI, 0.62-0.80).
In this comprehensive study, mammography screening for women ages 40 to 49 years was efficient for reducing breast cancer mortality.
Effectiveness of population-based service screening with mammography for women ages 40 to 49 years with a high or low risk of breast cancer: socioeconomic status, parity, and age at birth of first child.
Invitation to mammography screening of women aged 40 to 49 years is a matter of debate in many countries and a cost-effective alternative in countries without screening among women aged 40 to 49 years could be inviting those at higher risk. The relative effectiveness of mammography screening was estimated for subgroups based on the breast cancer risk factors parity, age at time of birth of first child, and socioeconomic status (SES).
The SCReening of Young Women (SCRY) database consists of all women aged 40 to 49 years in Sweden between 1986 and 2005 and was split into a study and control group. The study group consisted of women residing in areas in which women aged 40 to 49 years were invited to screening and the control group of women in areas in which women aged 40 to 49 years were not invited to screening. Rate ratio (RR) estimates were calculated for 2 exposures: invitation and attendance.
There were striking similarities noted in the RR pattern for women invited to and attending screening and no statistically significant difference or trend in the RR was noted by risk group. The RR estimates increased by increasing parity for parity of 0 to 2 and ranged from 0.55 (95% confidence interval [95% CI], 0.38-0.79) to 0.79 (95% CI, 0.65-0.95) for attending women. The RR for women with high SES was lower than that for women with low SES (RR, 0.72 [95% CI, 0.60-0.86] and RR, 0.79 [95% CI, 0.63-0.99], respectively). For women aged 20 to 24 years at the time of the birth of their first child, the RR was 0.73 (95% CI, 0.58-0.91) and estimates for other ages were similar.
There was no statistically significant difference noted in the relative effectiveness of mammography screening by parity, age at the time of birth of the first child, or SES.