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author:("gamo, Hans")
1.  Reducing the noise in signal detection of adverse drug reactions by standardizing the background: a pilot study on analyses of proportional reporting ratios-by-therapeutic area 
Purpose
Disproportionality screening analysis is acknowledged as a tool for performing signal detection in databases of adverse drug reactions (ADRs), e.g., in the European Union (EU) Drug Authority setting. The purpose of this study was to explore the possibility of decreasing false-positive signals of disproportionate reporting (SDR) by calculating the proportional reporting ratio (PRR)-by-therapeutic area (TA), while still maintaining the ability to detect relevant SDRs.
Methods
In the EudraVigilance (EV) Database, output from PRR calculated with a restricted TA comparator background was compared in detail to output from conventional authority-setting PRR calculations for four drugs: bicalutamide, abiraterone, metformin, and vildagliptin, within the TAs of prostate gland disease and type 2 diabetes mellitus.
Results
ADR reports per investigated drug ranged from 2,400 to 50,000. The PRR-TA’s ability to detect true-positive SDRs (as acknowledged in approved labeling) was increased compared to the conventional PRR, and performed 8–31 % better than a recently proposed stricter EU-SDR definition. The PRR-TA removed false SDRs confounded by disease or disease spill-over by up to 63 %, while retaining/increasing the number of unclassified SDRs relevant for manual validation, and thereby improving the ratio between confounded SDRs (i.e., noise) and unclassified SDRs for all investigated drugs (possible signals).
Conclusions
The performance of the PRR was improved by background restriction with the PRR-TA method; the number of false-positive SDRs decreased, and the ability to detect true-positive SDRs increased, improving the signal-to-noise ratio. Further development and validation of the method is needed within other TAs and databases, and for disproportionality analysis methods.
Electronic supplementary material
The online version of this article (doi:10.1007/s00228-014-1658-1) contains supplementary material, which is available to authorized users.
doi:10.1007/s00228-014-1658-1
PMCID: PMC3978377  PMID: 24599513
PRR; Adverse drug reactions; ADR; Signal detection; Pharmacovigilance; Disproportionality analysis
2.  Mortality following Hip Fracture in Men with Prostate Cancer 
PLoS ONE  2013;8(9):e74492.
Background
Hip fractures are associated with increased mortality and are a known adverse effect of androgen deprivation therapy (ADT) for prostate cancer (PCa). It was our aim to evaluate how mortality after hip fracture is modified by PCa and ADT.
Methods
PCa dataBase Sweden (PCBaSe 2.0) is based on the National PCa Register and also contains age and county-matched PCa-free men. We selected all men (n = 14,205) who had been hospitalized with a hip fracture between 2006 and 2010; 2,300 men had a prior PCa diagnosis of whom 1,518 (66%) were on ADT prior to date of fracture. Risk of death was estimated with cumulative incidence and standardized mortality ratios (SMRs) to make comparisons with the entire PCa population and the general population.
Results
Cumulative incidences indicated that there was a higher risk of death following a hip fracture for PCa men on ADT than for PCa men not on ADT or PCa-free men, particularly in the first year. The SMRs showed that PCa men on ADT with a hip fracture were 2.44 times more likely to die than the comparison cohort of all PCa men (95%CI: 2.29-2.60). This risk was especially increased during the first month (5.64 (95%CI: 4.16–7.48)). In absolute terms, hip fractures were associated with 20 additional deaths per 1,000 person-years in PCa men not on ADT, but 30 additional deaths per 1,000 person-years for PCa men on ADT, compared to all PCa men.
Conclusion
Hip fractures are associated with higher all-cause mortality in PCa men on ADT than in PCa men not on ADT or PCa-free men, especially within the first three months.
doi:10.1371/journal.pone.0074492
PMCID: PMC3785484  PMID: 24086350
3.  Results From the Scandinavian Prostate Cancer Group Trial Number 4: A Randomized Controlled Trial of Radical Prostatectomy Versus Watchful Waiting 
In the Scandinavian Prostate Cancer Group Trial Number 4 (SPCG-4), 347 men were randomly assigned to radical prostatectomy and 348 to watchful waiting. In the most recent analysis (median follow-up time = 12.8 years), the cumulative mortality curves had been stable over the follow-up. At 15 years, the absolute risk reduction of dying from prostate cancer was 6.1% following randomization to radical prostatectomy, compared with watchful waiting. Hence, 17 need to be randomized to operation to avert one death. Data on self-reported symptoms, stress from symptoms, and quality of life were collected at 4 and 12.2 years of median follow-up. These questionnaire studies show an intricate pattern of symptoms evolving after surgery, hormonal treatments, signs of tumor progression, and also from natural aging. This article discusses some of the main findings of the SPCG-4 study.
doi:10.1093/jncimonographs/lgs025
PMCID: PMC3540876  PMID: 23271778
4.  Individualized Estimation of the Benefit of Radical Prostatectomy from the Scandinavian Prostate Cancer Group Randomized Trial 
European Urology  2012;62(2):204-209.
Background
Although there is randomized evidence that radical prostatectomy improves survival, there are few data on how benefit varies by baseline risk.
Objective
We aimed to create a statistical model to calculate the decrease in risk of death associated with surgery for an individual patient, using stage, grade, prostate-specific antigen, and age as predictors.
Design, setting, and participants
A total of 695 men with T1 or T2 prostate cancer participated in the Scandinavian Prostate Cancer Group 4 trial (SPCG-4).
Intervention
Patients in SPCG-4 were randomized to radical prostatectomy or conservative management.
Outcome measurements and statistical analysis
Competing risk models were created separately for the radical prostatectomy and the watchful waiting group, with the difference between model predictions constituting the estimated benefit for an individual patient.
Results and limitations
Individualized predictions of surgery benefit varied widely depending on age and tumor characteristics. At 65 yr of age, the absolute 10-yr risk reduction in prostate cancer mortality attributable to radical prostatectomy ranged from 4.5% to 17.2% for low- versus high-risk patients. Little expected benefit was associated with surgery much beyond age 70. Only about a quarter of men had an individualized benefit within even 50% of the mean. A limitation is that estimates from SPCG-4 have to be applied cautiously to contemporary patients.
Conclusions
Our model suggests that it is hard to justify surgery in patients with Gleason 6, T1 disease or in those patients much above 70 yr of age. Conversely, surgery seems unequivocally of benefit for patients who have Gleason 8, or Gleason 7, stage T2. For patients with Gleason 6 T2 and Gleason 7 T1, treatment is more of a judgment call, depending on patient preference and other clinical findings, such as the number of positive biopsy cores and comorbidities.
doi:10.1016/j.eururo.2012.04.024
PMCID: PMC3389180  PMID: 22541389
Prostatic neoplasms; Statistics and research design; Randomized controlled trial; Prostatectomy
5.  Serum calcium and risk of gastrointestinal cancer in the Swedish AMORIS study 
BMC Public Health  2013;13:663.
Background
Observational studies have indicated that high calcium intake may prevent colorectal cancer, but as for randomized trials the results are inconclusive. Meanwhile, limited data on the link between serum calcium and cancer risk is available. We investigated the relation between serum calcium and risk of different gastrointestinal cancers in a prospective study.
Methods
A cohort based on 492,044 subjects with baseline information on calcium (mmol/L) and albumin (g/L) was selected from the Swedish Apolipoprotein MOrtality RISk (AMORIS) study. Multivariable Cox proportional hazard models were used to analyse associations between standardised levels, quartiles and age/sex-specific categories of serum calcium and risk of oesophageal, stomach, colon, rectal cancer and also colorectal cancer combined, while taking into account serum albumin and other comorbidities.
Results
During 12 years of follow-up, we identified 323 incident oesophageal cancers, 782 stomach cancers, 2519 colon cancers, and 1495 rectal cancers. A positive association was found between albumin-adjusted serum calcium and risk of oesophageal [HR: 4.82 (95% CI: 2.07 – 11.19) for high compared to normal age-specific calcium levels] and colon cancer [e.g. HR: 1.07 (95% CI: 1.00 – 1.14) for every SD increase of calcium] as well as colorectal cancer [e.g. HR: 1.06 (95% CI: 1.02-1.11) for every SD increase of calcium] in women. In men there were similar but weaker non-statistically significant trends.
Conclusion
The positive relation between serum calcium, oesophageal cancer and colorectal cancer calls for further studies including calcium regulators to evaluate whether there is a true link between calcium metabolism and development of gastrointestinal cancer.
doi:10.1186/1471-2458-13-663
PMCID: PMC3729677  PMID: 23866097
Gastrointestinal cancer; Calcium; Albumin
6.  Inorganic phosphate and the risk of cancer in the Swedish AMORIS study 
BMC Cancer  2013;13:257.
Background
Both dietary and serum levels of inorganic phosphate (Pi) have been linked to development of cancer in experimental studies. This is the first population-based study investigating the relation between serum Pi and risk of cancer in humans.
Methods
From the Swedish Apolipoprotein Mortality Risk (AMORIS) study, we selected all participants (> 20 years old) with baseline measurements of serum Pi, calcium, alkaline phosphatase, glucose, and creatinine (n = 397,292). Multivariable Cox proportional hazards regression analyses were used to assess serum Pi in relation to overall cancer risk. Similar analyses were performed for specific cancer sites.
Results
We found a higher overall cancer risk with increasing Pi levels in men ( HR: 1.02 (95% CI: 1.00-1.04) for every SD increase in Pi), and a negative association in women (HR: 0.97 (95% CI: 0.96-0.99) for every SD increase in Pi). Further analyses for specific cancer sites showed a positive link between Pi quartiles and the risk of cancer of the pancreas, lung, thyroid gland and bone in men, and cancer of the oesophagus, lung, and nonmelanoma skin cancer in women. Conversely, the risks for developing breast and endometrial cancer as well as other endocrine cancer in both men and women were lower in those with higher Pi levels.
Conclusions
Abnormal Pi levels are related to development of cancer. Furthermore, the in verse association between Pi levels and risk of breast, endometrial and other endocrine cancers may indicate the role of hormonal factors in the relation between Pi metabolism and cancer.
doi:10.1186/1471-2407-13-257
PMCID: PMC3664604  PMID: 23706176
Cancer; Inorganic phosphate; Prospective cohort study
7.  Iron metabolism and risk of cancer in the Swedish AMORIS study 
Cancer Causes & Control  2013;24(7):1393-1402.
Objectives
Pre-clinical studies have shown that iron can be carcinogenic, but few population-based studies investigated the association between markers of the iron metabolism and risk of cancer while taking into account inflammation. We assessed the link between serum iron (SI), total-iron binding capacity (TIBC), and risk of cancer by levels of C-reactive protein (CRP) in a large population-based study (n = 220,642).
Methods
From the Swedish Apolipoprotein Mortality Risk (AMORIS) study, we selected all participants (>20 years old) with baseline measurements of serum SI, TIBC, and CRP. Multivariate Cox proportional hazards regression was carried out for standardized and quartile values of SI and TIBC. Similar analyses were performed for specific cancers (pancreatic, colon, liver, respiratory, kidney, prostate, stomach, and breast cancer). To avoid reverse causation, we excluded those with follow-up <3 years.
Results
We found a positive association between standardized TIBC and overall cancer [HR 1.03 (95 % CI 1.01–1.05)]. No statistically significant association was found between SI and cancer risk except for postmenopausal breast cancer [HR for standardized SI 1.09 (95 % CI 1.02–1.15)]. The association between TIBC and specific cancer was only statistically significant for colon cancer [i.e., HR for standardized TIBC: 1.17 (95 % CI 1.08–1.28)]. A borderline interaction between SI and levels of CRP was observed only in stomach cancer.
Conclusions
As opposed to pre-clinical findings for serum iron and cancer, this population-based epidemiological study showed an inverse relation between iron metabolism and cancer risk. Minimal role of inflammatory markers observed warrants further study focusing on developments of specific cancers.
doi:10.1007/s10552-013-0219-8
PMCID: PMC3675271  PMID: 23649231
Cancer; C-reactive protein; Iron; Iron-binding capacity; Sweden
8.  Serum Glucose and Fructosamine in Relation to Risk of Cancer 
PLoS ONE  2013;8(1):e54944.
Background
Impaired glucose metabolism has been linked with increased cancer risk, but the association between serum glucose and cancer risk remains unclear. We used repeated measurements of glucose and fructosamine to get more insight into the association between the glucose metabolism and risk of cancer.
Methods
We selected 11,998 persons (>20 years old) with four prospectively collected serum glucose and fructosamine measurements from the Apolipoprotein Mortality Risk (AMORIS) study. Multivariate Cox proportional hazards regression was used to assess standardized log of overall mean glucose and fructosamine in relation to cancer risk. Similar analyses were performed for tertiles of glucose and fructosamine and for different types of cancer.
Results
A positive trend was observed between standardized log overall mean glucose and overall cancer risk (HR = 1.08; 95% CI: 1.02–1.14). Including standardized log fructosamine in the model resulted in a stronger association between glucose and cancer risk and aninverse association between fructosamine and cancer risk (HR = 1.17; 95% CI: 1.08–1.26 and HR: 0.89; 95% CI: 0.82–0.96, respectively). Cancer risks were highest among those in the highest tertile of glucose and lowest tertile of fructosamine. Similar findings were observed for prostate, lung, and colorectal cancer while none observed for breast cancer.
Conclusion
The contrasting effect between glucose, fructosamine, and cancer risk suggests the existence of distinct groups among those with impaired glucose metabolism, resulting in different cancer risks based on individual metabolic profiles. Further studies are needed to clarify whether glucose is a proxy of other lifestyle-related or metabolic factors.
doi:10.1371/journal.pone.0054944
PMCID: PMC3556075  PMID: 23372798
9.  Gamma-glutamyl transferase and C-reactive protein as alternative markers of metabolic abnormalities and their associated comorbidites: a prospective cohort study 
Background: Recent studies suggested that gamma-glutamyl transferase (GGT) and C-reactive protein (CRP) are good markers of metabolic abnormalities. We assessed the link between GGT, CRP and common metabolic abnormalities, as well their link to related diseases, such as cancer and cardiovascular disease (CVD). Methods: We selected 333,313 subjects with baseline measurements of triglycerides (TG), total cholesterol (TC), glucose, GGT and CRP in the Swedish AMORIS study. Baseline measurement of BMI was available for 63,900 persons and 77,944 had baseline measurements of HDL. Pearson correlation coefficients between CRP, GGT, and metabolic components (TG, HDL, BMI and TC) were calculated. To investigate the combined effect of GGT and CRP we created a score ranging from 0 to 6 and used Cox proportional hazard models to evaluate its association with CVD and cancer. Results: 21,216 individuals developed cancer and 47,939 CVD. GGT and TG had the strongest correlation (r=0.22). An increased risk of cancer was identified with elevated levels of GGT or CRP or both markers (GGT-CRP score ≥3); the greatest risk of cancer was found when GGT-CRP score = 6 (HR: 1.40 (95%CI: 1.31-1.48) and 1.60 (1.47-1.76) compared to GGT-CRP score = 0, respectively). Conclusion: While GGT and CRP have been shown to be associated with metabolic abnormalities previously, their association to the components investigated in this study was limited. Results did demonstrate that these markers were predictive of associated diseases, such as cancer.
PMCID: PMC3508539  PMID: 23205179
GGT; CRP; metabolic abnormalities; cardiovascular disease; cancer
10.  Serum Lipids and the Risk of Gastrointestinal Malignancies in the Swedish AMORIS Study 
Journal of Cancer Epidemiology  2012;2012:792034.
Background. Metabolic syndrome has been linked to an increased cancer risk, but the role of dyslipidaemia in gastrointestinal malignancies is unclear. We aimed to assess the risk of oesophageal, stomach, colon, and rectal cancers using serum levels of lipid components. Methods. From the Swedish Apolipoprotein Mortality Risk (AMORIS) study, we selected 540,309 participants (> 20 years old) with baseline measurements of total cholesterol (TC), triglycerides (TG), and glucose of whom 84,774 had baseline LDL cholesterol (LDL), HDL cholesterol (HDL), apolipoprotein B (apoB), and apolipoprotein A-I (apoA-I). Multivariate Cox proportional hazards regression was used to assess glucose and lipid components in relation to oesophageal, stomach, colon, and rectal cancer risk. Results. An increased risk of oesophageal cancer was observed in persons with high TG (e.g. HR: 2.29 (95% CI: 1.42–3.68) for the 4th quartile compared to the 1st) and low LDL, LDL/HDL ratio, TC/HDL ratio, log (TG/HDL), and apoB/apoA-I ratio. High glucose and TG were linked with an increased colon cancer risk, while high TC levels were associated with an increased rectal cancer risk. Conclusion. The persistent link between TC and rectal cancer risk as well as between TG and oesophageal and colon cancer risk in normoglycaemic individuals may imply their substantiality in gastrointestinal carcinogenesis.
doi:10.1155/2012/792034
PMCID: PMC3437288  PMID: 22969802
11.  Lipid profiles and the risk of endometrial cancer in the Swedish AMORIS study 
Background
While the association between obesity and endometrial cancer (EC) is well established, the underlying mechanisms require further study. We assessed possible links between lipid profiles and EC risk, while also taking into account BMI, parity, and menopausal status at baseline.
Methods
Using the information available from the Swedish Apolipoprotein MOrtality RISk (AMORIS) study we created a cohort of 225,432 women with baseline values for glucose, triglycerides (TG), and total cholesterol (TC). Two subgroups of 31,792 and 26,317 had, in addition, baseline measurements of HDL, LDL, apolipoprotein A-I and apoB and BMI, respectively. We used Multivariate Cox proportional hazards models to analyze quartiles and dichotomized values of these lipid components for a link to EC risk.
Results
During mean follow-up of 12 years (SD: 4.15), 1,144 persons developed endometrial cancer. A statistically significant association was found between TG and EC risk when using both quartiles and a clinical cut-off (Hazard Ratio (HR): 1.10 (95%CI: 0.88-1.37), 1.34 (1.09-1.63), and 1.57 (1.28-1.92)) for the 2nd, 3rd, and 4th quartile, compared to the 1st, with P-value for trend: <0.001). The association remained after exclusion of the first three years of follow-up. Also total cholesterol and TG/HDL ratio were positively associated with EC risk, but no link was found for the other lipid components studied.
Conclusion
This detailed analysis of lipid components showed a consistent relation between TG levels and EC risk. Future research should continue to analyze the metabolic pathway and its relation to EC risk, as a pathway to further understand the relation of obesity and disease.
PMCID: PMC3376923  PMID: 22724049
Lipid profiles; risk factor; endometrial cancer; Swedish AMORIS study
12.  Seasonal variations of insulin sensitivity from a euglycemic insulin clamp in elderly men 
Introduction.
Seasonal variations in hemoglobin-A1c have been reported in diabetic patients, but the underlying mechanisms have not been elucidated.
Aims.
To study if insulin sensitivity, insulin secretion, and fasting plasma glucose showed seasonal variations in a Swedish population-based cohort of elderly men.
Methods.
Altogether 1117 men were investigated with a euglycemic insulin clamp and measurements of fasting plasma glucose and insulin secretion after an oral glucose tolerance test. Values were analyzed in linear regression models with an indicator variable for winter/summer season and outdoor temperature as predictors.
Results.
During winter, insulin sensitivity (M/I, unit = 100 × mg × min-1 × kg-1/(mU × L-1)) was 11.0% lower (4.84 versus 5.44, P = 0.0003), incremental area under the insulin curve was 16.4% higher (1167 versus 1003 mU/L, P = 0.007). Fasting plasma glucose was, however, not statistically significantly different (5.80 versus 5.71 mmol/L, P = 0.28) compared to the summer season. There was an association between outdoor temperature and M/I (0.57 units increase (95% CI 0.29–0.82, P < 0.0001) per 10°C increase of outdoor temperature) independent of winter/summer season. Adjustment for life-style factors, type 2 diabetes, and medication did not alter these results.
Conclusions.
Insulin sensitivity showed seasonal variations with lower values during the winter and higher during the summer season. Inverse compensatory variations of insulin secretion resulted in only minor variations of fasting plasma glucose. Insulin sensitivity was associated with outdoor temperature. These phenomena should be further investigated in diabetic patients.
doi:10.3109/03009734.2011.628422
PMCID: PMC3282240  PMID: 22066936
Insulin secretion; insulin sensitivity; seasonal variation
13.  Biomarker-based score to predict mortality in persons aged 50 years and older: a new approach in the Swedish AMORIS study 
Background
Management of frailty is the cornerstone of geriatric medicine, but there remains a need to identify biomarkers that can predict early death, and thereby lead to effective clinical interventions. We aimed to study the combination of C-reactive protein (CRP), albumin, gamma-glutamyl transferase (GGT), and HDL to predict mortality.
Methods
A total of 44,457 persons aged 50+ whose levels of CRP, albumin, GGT, and HDL were measured at baseline were selected from the Swedish Apolipoprotein MOrtality RISk (AMORIS) study. A mortality score, ranging from 0 to 4, was created by adding the number of markers with abnormal values according to the clinical cut-off (CRP > 10 mg/L, albumin < 35 mg/L, GGT > 36 kU/L, HDL < 1.04 mmol/L). Mortality was studied with multivariate Cox proportional hazards models.
Results
2,245 persons died from cancer, 3,276 from circulatory disease, and 1,860 from other causes. There was a positive trend between mortality score and all-cause mortality as well as cancer and circulatory disease-specific death (e.g. HR for all-cause mortality: 1.39 (95%CI: 1.32-1.46), 2.04 (1.89-2.21), and 3.36 (2.87-3.93), for score=1, 2, and 3+, compared to score=0). Among cancer patients with no other co-morbidities (n=1,955), there was a positive trend between the score and mortality (HR: 1.24 (95%CI: 1.0.-1.49), 2.38 (95%CI: 1.76-3.22), and 5.47 (95%CI: 2.98-10.03) for score=1, 2, and 3+ compared to score=0).
Conclusions
By combining biomarkers of different mechanisms contributing to patient frailty, we found a strong marker for mortality in persons aged 50+. Elevated risks among cancer patients with no other co-morbidities prior to biomarker assessment call for validation in other cohorts and testing of different combinations and cut-offs than those used here, in order to aid decision-making in treatment of older cancer patients.
PMCID: PMC3316450  PMID: 22493753
Frailty; mortality; albumin; HDL-cholesterol; C-reactive protein; gamma-glutamyltransferase
14.  Serum levels of selenium and smoking habits at age 50 influence long term prostate cancer risk; a 34 year ULSAM follow-up 
BMC Cancer  2011;11:431.
Background
Serum selenium level (s-Se) has been associated with prostate cancer (PrCa) risk. We investigated the relation between s-Se, smoking and non-screening detected PrCa and explored if polymorphisms in two DNA repair genes: OGG1 and MnSOD, influenced any effect of s-Se.
Methods
ULSAM, a population based Swedish male cohort (n = 2322) investigated at age 50 for s-Se and s-Se influencing factors: serum cholesterol, erythrocyte sedimentation rate and smoking habits. At age 71 a subcohort, (n = 1005) was genotyped for OGG1 and MnSOD polymorphisms.
Results
In a 34-year-follow-up, national registries identified 208 PrCa cases further confirmed in medical records. Participants with s-Se in the upper tertile had a non-significantly lower risk of PrCa. Smokers with s-Se in the two lower tertiles (≤80 μg/L) experienced a higher cumulative incidence of PrCa than smokers in the high selenium tertile (Hazard Ratio 2.39; 95% CI: 1.09-5.25). A high tertile selenium level in combination with non-wt rs125701 of the OGG1 gene in combination with smoking status or rs4880 related variation of MnSOD gene appeared to protect from PrCa.
Conclusions
S-Se levels and smoking habits influence long-term risk of PrCa. Smoking as a risk factor for PrCa in men with low s-Se is relevant to explore further. Exploratory analyses of variations in OGG1 and MnSOD genes indicate that hypotheses about patterns of exposure to selenium and smoking combined with data on genetic variation in genes involved in DNA repair can be valuable to pursue.
doi:10.1186/1471-2407-11-431
PMCID: PMC3199281  PMID: 21982398
15.  Association between levels of C-reactive protein and leukocytes and cancer: Three repeated measurements in the Swedish AMORIS study 
Objective
To study levels of C-reactive protein (CRP) and leukocytes, as inflammatory markers, in the context of cancer risk.
Methods
From the Apolipoprotein MOrtality RISk (AMORIS) study, we selected 102,749 persons with one measurement and 9,273 persons with three repeated measurements of CRP and leukocytes. Multivariate Cox proportional hazards regression was applied to categories of CRP (<10, 10-15, 15-25, 25-50, >50 g/L) and quartiles of leukocytes. An Inflammation-based Predictive Score (IPS) indicated whether someone had CRP levels >10mg/L combined with leukocytes >10×109/L. Reverse causality was assessed by excluding those with <3, 5, or 7 years of follow-up. To analyze repeated measurements of CRP and leukocytes the repeated IPS (IPSr) was calculated by adding the IPS of each measurement.
Results
In the cohort with one measurement, there was a positive trend between CRP and cancer, with the lowest category being the reference: 0.99 (0.92-1.06), 1.28 (1.11-1.47), 1.27 (1.09-1.49), 1.22 (1.01-1.48) for the 2nd to 5th categories, respectively. This association disappeared when excluding those with follow-up <3, 5 or 7 years. The association between leukocytes and cancer was slightly stronger. In the cohort with repeated measurements the IPSr was strongly associated with cancer risk: 1.87 (1.33-2.63), 1.51 (0.56-4.06), 4.46 (1.43-13.87) for IPSr =1, 2, and 3, compared to IPSr =0. The association remained after excluding those with follow-up <1 year.
Conclusions and impact
Our large prospective cohort study adds evidence for a link between inflammatory markers and cancer risk by using repeated measurements and ascertaining reverse causality.
doi:10.1158/1055-9965.EPI-10-1190
PMCID: PMC3078551  PMID: 21297038
cancer; C-reactive protein; leukocytes; Sweden
16.  The metabolic syndrome and the risk of prostate cancer under competing risks of death from other causes 
Background
Associations between Metabolic Syndrome (MetS) components and prostate cancer development have not been studied comprehensively; results have been divergent. Using the National Cholesterol Education Program Adult Treatment panel III (NCEP) and International Diabetes Federation (IDF) definitions of the MetS we investigated such associations taking competing risks of death into consideration.
Methods
In the prospective Uppsala Longitudinal Study of Adult Men (ULSAM) of 2322 Caucasian men with 34 years of follow-up baseline MetS-measurements at age 50 were used. Cumulative incidence of prostate cancer and death with/without the MetS were calculated. Competing risk of dying was taken into account by calculating the conditional probability of prostate cancer with/without the MetS.
Results
Two-hundred-and- thirty-seven prostate cancers were identified. Prostate cancer probability by age 80 with baseline MetS compared to without the MetS was non-significantly higher, 5.2 percent-units (CI -0.8%-11.3%, (NCEP), 2.7 percent-units (CI -2.7%-8.0%) (IDF), cumulative incidence proportions of death was significantly higher, 19.3 percent-units (CI 13.4%-25.3%) (NCEP), 15.3 percent-units (CI 9.5%-21.1%) (IDF) and conditional probability of prostate cancer considering death from other causes was significantly higher, 7.3 percent-units (CI 0.2%-14.5%) odds ratio(OR) of 1.64 (CI 1.03-2.23). (NCEP), and non-significantly higher 5.0 percent-units (CI -1.6%-11.6%) OR 1.43 (CI 0.89-1.90). (IDF).
Conclusions
The MetS by the NCEP definition is associated with prostate cancer taking the competing risk of early death from other causes into account.
Impact
The results further highlight the public health impact of the increasing prevalence of MetS, and the importance of considering competing risks when studying risk factors for cancer.
doi:10.1158/1055-9965.EPI-10-0112
PMCID: PMC2923431  PMID: 20647401
epidemiology; prostate cancer; metabolic syndrome; competing risk; risk factors
17.  Development of a New Method for Monitoring Prostate-Specific Antigen Changes in Men with Localised Prostate Cancer: A Comparison of Observational Cohorts 
European urology  2009;57(3):446-452.
Background
Prostate-specific antigen (PSA) measurements are increasingly used to monitor men with localised prostate cancer (PCa), but there is little consensus about the method to use.
Objective
To apply age-specific predictions of PSA level (developed in men without cancer) to one cohort of men with clinically identified PCa and one cohort of men with PSA-detected PCa. We hypothesise that among men with clinically identified cancer, the annual increase in PSA level would be steeper than in men with PSA-detected cancer.
Design, setting, and participants
The Scandinavian Prostatic Cancer Group 4 (SPCG-4) cohort consisted of 321 men assigned to the watchful waiting arm of the SPCG-4 trial. The UK cohort consisted of 320 men with PSA-detected PCa in the Prostate Testing for Cancer and Treatment (ProtecT) study in nine UK centres between 1999 and 2007 who opted for monitoring rather than treatment. Multilevel models describing changes in PSA level were fitted to the two cohorts, and average PSA level at age 50, change in PSA level with age, and predicted PSA values were derived.
Measurements
PSA level.
Results and limitations
In the SPCG-4 cohort, mean PSA at age 50 was similar to the cancer-free cohort but with a steeper yearly increase in PSA level (16.4% vs 4.0%). In the UK cohort, mean PSA level was higher than that in the cancer-free cohort (due to a PSA biopsy threshold of 3.0 ng/ml) but with a similar yearly increase in PSA level (4.1%). Predictions were less accurate for the SPCG-4 cohort (median observed minus predicted PSA level: −2.0 ng/ml; interquartile range [IQR]: −7.6–0.7 ng/ml) than for the UK cohort (median observed minus predicted PSA level: −0.8 ng/ml; IQR: −2.1–0.1 ng/ml).
Conclusions
In PSA-detected men, yearly change in PSA was similar to that in cancer-free men, whereas in men with symptomatic PCa, the yearly change in PSA level was considerably higher. Our method needs further evaluation but has promise for refining active monitoring protocols.
doi:10.1016/j.eururo.2009.03.023
PMCID: PMC2910432  PMID: 19303695
active surveillance; localised prostate cancer; PSA doubling time; PSA velocity; reference ranges
18.  Risk of thromboembolic diseases in men with prostate cancer: results from the population-based PCBaSe Sweden 
The Lancet Oncology  2010;11(5):450-458.
Summary
Background
Cancer is associated with an increased risk of thromboembolic diseases, but data on the association between prostate cancer and thromboembolic diseases are scarce. We investigated the risk of thromboembolic disease in men with prostate cancer who were receiving endocrine treatment, curative treatment, or surveillance.
Methods
We analysed data from PCBaSe Sweden, a database based on the National Prostate Cancer Register, which covers over 96% of prostate cancer cases in Sweden. Standardised incidence ratios (SIR) of deep-venous thrombosis (DVT), pulmonary embolism, and arterial embolism were calculated by comparing observed and expected (using the total Swedish male population) occurrences of thromboembolic disease, taking into account age, calendar-time, number of thromboembolic diseases, and time since previous thromboembolic disease.
Findings
Between Jan 1, 1997, and Dec 31, 2007, 30 642 men received primary endocrine therapy, 26 432 curative treatment, and 19 526 surveillance. 1881 developed a thromboembolic disease. For men on endocrine therapy, risks for DVT (SIR 2·48, 95% CI 2·25–2·73) and pulmonary embolism (1·95, 1·81–2·15) were increased, although this was not the case for arterial embolism (1·00, 0·82–1·20). Similar patterns were seen for men who received curative treatment (DVT: 1·73, 1·47–2·01; pulmonary embolism: 2·03, 1·79–2·30; arterial embolism: 0·95, 0·69–1·27) and men who were on surveillance (DVT: 1·27, 1·08–1·47; pulmonary embolism: 1·57, 1·38–1·78; arterial embolism: 1·08, 0·87–1·33). Increased risks for thromboembolic disease were maintained when patients were stratified by age and tumour stage.
Interpretation
All men with prostate cancer were at higher risk of thromboembolic diseases, with the highest risk for those on endocrine therapy. Our results indicate that prostate cancer itself, prostate cancer treatments, and selection mechanisms all contribute to increased risk of thromboembolic disease. Thromboembolic disease should be a concern when managing patients with prostate cancer.
Funding
Swedish Research Council, Stockholm Cancer Society, and Cancer Research UK.
doi:10.1016/S1470-2045(10)70038-3
PMCID: PMC2861771  PMID: 20395174
19.  Radical Prostatectomy Versus Watchful Waiting in Localized Prostate Cancer: the Scandinavian Prostate Cancer Group-4 Randomized Trial 
Background
The benefit of radical prostatectomy in patients with early prostate cancer has been assessed in only one randomized trial. In 2005, we reported that radical prostatectomy improved prostate cancer survival compared with watchful waiting after a median of 8.2 years of follow-up. We now report results after 3 more years of follow-up.
Methods
From October 1, 1989, through February 28, 1999, 695 men with clinically localized prostate cancer were randomly assigned to radical prostatectomy (n = 347) or watchful waiting (n = 348). Follow-up was complete through December 31, 2006, with histopathologic review and blinded evaluation of causes of death. Relative risks (RRs) were estimated using the Cox proportional hazards model. Statistical tests were two-sided.
Results
During a median of 10.8 years of follow-up (range = 3 weeks to 17.2 years), 137 men in the surgery group and 156 in the watchful waiting group died (P = .09). For 47 of the 347 men (13.5%) who were randomly assigned to surgery and 68 of the 348 men (19.5%) who were not, death was due to prostate cancer. The difference in cumulative incidence of death due to prostate cancer remained stable after about 10 years of follow-up. At 12 years, 12.5% of the surgery group and 17.9% of the watchful waiting group had died of prostate cancer (difference = 5.4%, 95% confidence interval [CI] = 0.2 to 11.1%), for a relative risk of 0.65 (95% CI = 0.45 to 0.94; P = .03). The difference in cumulative incidence of distant metastases did not increase beyond 10 years of follow-up. At 12 years, 19.3% of men in the surgery group and 26% of men in the watchful waiting group had been diagnosed with distant metastases (difference = 6.7%, 95% CI = 0.2 to 13.2%), for a relative risk of 0.65 (95% CI = 0.47 to 0.88; P = .006). Among men who underwent radical prostatectomy, those with extracapsular tumor growth had 14 times the risk of prostate cancer death as those without it (RR = 14.2, 95% CI = 3.3 to 61.8; P < .001).
Conclusion
Radical prostatectomy reduces prostate cancer mortality and risk of metastases with little or no further increase in benefit 10 or more years after surgery.
doi:10.1093/jnci/djn255
PMCID: PMC2518167  PMID: 18695132
20.  Use of 5α-reductase inhibitors for lower urinary tract symptoms and risk of prostate cancer in Swedish men: nationwide, population based case-control study 
Objective To assess the association between 5α-reductase inhibitor (5-ARI) use in men with lower urinary tract symptoms and prostate cancer risk.
Design Nationwide, population based case-control study for men diagnosed with prostate cancer in 2007-09 within the Prostate Cancer data Base Sweden 2.0.
Setting The National Prostate Cancer Register, National Patient Register, census, and Prescribed Drug Register in Sweden, from which we obtained data on 5-ARI use before date of prostate cancer diagnosis.
Participants 26 735 cases and 133 671 matched controls; five controls per case were randomly selected from matched men in the background population. 7815 men (1499 cases and 6316 controls) had been exposed to 5-ARI. 412 men had been exposed to 5-ARI before the diagnosis of a cancer with Gleason score 8-10.
Main outcome measures Risk of prostate cancer calculated as odds ratios and 95% confidence intervals by conditional logistic regression analyses.
Results Risk of prostate cancer overall decreased with an increasing duration of exposure; men on 5-ARI treatment for more than three years had an odds ratio of 0.72 (95% confidence interval 0.59 to 0.89; P<0.001 for trend). The same pattern was seen for cancers with Gleason scores 2-6 and score 7 (both P<0.001 for trend). By contrast, the risk of tumours with Gleason scores 8-10 did not decrease with increasing exposure time to 5-ARI (for 0-1 year of exposure, odds ratio 0.96 (95% confidence interval 0.83 to 1.11); for 1-2 years, 1.07 (0.88 to 1.31); for 2-3 years, 0.96 (0.72 to 1.27); for >3 years, 1.23 (0.90 to 1.68); P=0.46 for trend).
Conclusions Men treated with 5-ARI for lower urinary tract symptoms had a decreased risk of cancer with Gleason scores 2-7, and showed no evidence of an increased risk of cancer with Gleason scores 8-10 after up to four years’ treatment.
doi:10.1136/bmj.f3406
PMCID: PMC3685512  PMID: 23778271
21.  Fatherhood status and risk of prostate cancer: Nationwide, population-based case–control study 
Previous studies have shown a decreased risk of prostate cancer for childless men; however, the cause of the association remains to be elucidated. The aim of our study was to assess the risk of prostate cancer by fatherhood status, also considering potential confounding factors. In a case–control study in Prostate Cancer data Base Sweden 2.0, a nationwide, population-based cohort, data on number of children, marital status, education, comorbidity and tumor characteristics obtained through nationwide healthcare registers and demographic databases for 117,328 prostate cancer cases and 562,644 controls, matched on birth year and county of residence, were analyzed. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for prostate cancer overall and by risk category, adjusting for marital status and education. Childless men had a decreased risk of prostate cancer compared to fathers, OR = 0.83 (95% CI = 0.82–0.84), and risk was lower for low-risk prostate cancer, OR = 0.74 (95% CI = 0.72–0.77), than for metastatic prostate cancer, OR = 0.93 (95% CI = 0.90–0.97). Adjustment for marital status and education attenuated the association in the low-risk category, adjusted OR = 0.87 (95% CI = 0.84–0.91), whereas OR for metastatic cancer remained virtually unchanged, adjusted OR = 0.92 (95% CI = 0.88–0.96). Our data indicate that the association between fatherhood status and prostate cancer to a large part is due to socioeconomic factors influencing healthcare-seeking behavior including testing of prostate-specific antigen levels.
doi:10.1002/ijc.28057
PMCID: PMC3734704  PMID: 23354735
prostate cancer; epidemiology; case–control studies; hypogonadism; androgens
22.  Population-based study on use of chemotherapy in men with castration resistant prostate cancer 
Acta Oncologica (Stockholm, Sweden)  2013;52(8):1593-1601.
Background.
Chemotherapy prolongs life and relieves symptoms in men with castration resistant prostate cancer (CRPC). There is limited information on a population level on the use of chemotherapy for CRPC.
Material and methods.
To assess the use of chemotherapy in men with CRPC we conducted a register-based nationwide population-based study in Prostate Cancer data Base Sweden (PCBaSe) and a nationwide in-patient drug register (SALT database) between May 2009 and December 2010. We assumed that men who died of prostate cancer (PCa) underwent a period of CRPC before they died.
Results.
Among the 2677 men who died from PCa during the study inclusion period, 556 (21%) had received chemotherapy (intravenous or per oral) detectable within the observation period in SALT database. Specifically, 239 (61%) of men < 70 years had received chemotherapy, 246 (30%) of men between 70 and 79 years and 71 (5%) men older than 80 years. The majority of men 465/556 (84%) had received a docetaxel-containing regimen. Among chemotherapy treated men, 283/556 (51%) received their last dose of chemotherapy during the last six months prior to death. Treatment with chemotherapy was more common among men with little comorbidity and high educational level, as well as in men who had received curatively intended primary treatment.
Conclusion.
A majority of men younger than 70 years with CRPC were treated with chemotherapy in contrast to men between 70 and 79 years of whom half as many received chemotherapy. Chemotherapy treatment was often administered shortly prior to death. The low uptake of chemotherapy in older men with CRPC may be caused by concerns about tolerability of treatment, as well as treatment decisions based on chronological age rather than global health status.
doi:10.3109/0284186X.2013.770164
PMCID: PMC3812701  PMID: 23427879

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