Hospitalisation for venous thromboembolism in cancer patients and the general population: a population-based cohort study in Denmark, 1997-2006

Background:

Venous thromboembolism (VTE) frequently complicates cancer. Data on tumour-specific VTE predictors are limited, but may inform strategies to prevent thrombosis.

Methods:

We computed incidence rates (IRs) with 95% confidence intervals (CIs) for VTE hospitalisation in a cohort of cancer patients (n=57 591) and in a comparison general-population cohort (n=287 476) in Denmark. The subjects entered the study in 1997–2005, and the follow-up continued through 2006. Using Cox proportional-hazards regression, we estimated relative risks (RRs) for VTE predictors, while adjusting for comorbidity.

Results:

Throughout the follow-up, VTE IR was higher among the cancer patients (IR=8.0, 95% CI=7.6–8.5) than the general population (IR=4.7, 95% CI=4.3–5.1), particularly in the first year after cancer diagnosis (IR=15.0, 95% CI=13.8–16.2, vs IR=8.6, 95% CI=7.6–9.9). Incidence rates of VTE were highest in patients with pancreas (IR=40.9, 95% CI=29.5–56.7), brain (IR=17.7, 95% CI=11.3–27.8) or liver (IR=20.4, 95% CI=9.2–45.3) tumours, multiple myeloma (IR=22.6, 95% CI=15.4–33.2) and among patients with advanced-stage cancers (IR=27.7, 95% CI=24.0–32.0) or those who received chemotherapy or no/symptomatic treatment. The adjusted RR (aRR) for VTE was highest among patients with pancreas (aRR=16.3, 95% CI=8.1–32.6) or brain cancer (aRR=19.8 95% CI=7.1–55.2), multiple myeloma (aRR=46.1, 95% CI=13.1–162.0) and among patients receiving chemotherapy, either alone (aRR=18.5, 95% CI=11.9–28.7) or in combination treatments (aRR=16.2, 95% CI=12.0–21.7).

Conclusions:

Risk of VTE is higher among cancer patients than in the general population. Predictors of VTE include recency of cancer diagnosis, cancer site, stage and the type of cancer-directed treatment.

Survival associated with bone metastases and skeletal-related events in breast cancer patients: A population-based cohort study in Denmark (1999 - 2007)

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Background: Breast cancer (BrCa) is the most commonly diagnosed cancer for women in the industrialized world. Among women who present with metastatic BrCa, more than half will develop bone metastases. Bone metastases increase the risk for skeletal-related events (SREs) defined as radiation to bone, pathologic fractures, spinal cord compression, surgery to bone, or change in antineoplastic therapy to treat bone pain. These complications are associated with an unfavorable prognosis and have a major impact on patients' quality of life. However, data on survival of BrCa patients who experience SREs are lacking. We evaluated survival among BrCa patients without bone metastases, with bone metastases, and with both bone metastases and SREs. Methods: Using Denmark's National Registry of Patients (NRP) database, we conducted a retrospective cohort study in the North and Mid- Jutland Region. Patients with a diagnosis of BrCa from January 1, 1999 through December 31, 2007 were identified using the International Classification of Diseases, 10th Revision (ICD-10) codes C50.x. SREs after BrCa diagnosis were identified using the ICD-10 code C79.5. Cox proportional-hazards regression was used to estimate the mortality rate ratio (MRR), adjusting for age and comorbidity, to compare survival among three subgroups of BrCa patients: no bone metastases, bone metastases, and bone metastases with SREs. Results: We identified 9,474 BrCa patients from the NRP. Of these, 621 (7%) developed bone metastases and 267 (3%) developed both bone metastases and SREs during the study period. The 5-year mortality rates among BrCa patients without bone metastases, with bone metastases, and with bone metastases and SREs were 50.7 per 1,000 person-years (PYs), 469 per 1,000 PYs, and 712 per 1,000 PYs, respectively. Compared to BrCa patients without bone metastases, the adjusted MRRs among BrCa patients with bone metastases and patients with bone metastases and SREs were 11.6 [95% confidence interval (CI): 10.9 - 13.6] and 18.1 (95% CI: 15.5 - 21.0), respectively. Conclusions: Our results suggest that bone metastases and SREs have a major impact on the overall mortality of BrCa patients in Denmark.

[Table: see text]

Incidence of acute kidney injury in cancer patients: A population-based cohort study in Denmark

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Background: Although cancer patients may be at increased risk for acute kidney injury (AKI), which could then reduce their likelihood of receiving optimal therapeutic management and supportive care, the occurrence of AKI among newly diagnosed cancer patients has not been well-described. Therefore, we examined the incidence of AKI within the first year after cancer diagnosis to estimate the magnitude of this risk and better understand which patients are at greatest risk. Methods: Using the population-based Danish Cancer Registry, we conducted a retrospective cohort study of 4,427 men and women from North Jutland, Denmark (population 500,000) diagnosed with cancer from 2002 to 2003 (non-melanoma skin cancer excluded). AKI was defined according to the Risk/ Injury/ Failure/ Loss/ End-stage-renal-disease (RIFLE) criteria. We included Risk or worse: at least a 1.5 times increase in serum creatinine (sCr) from baseline. SCr levels were obtained from the Regional Laboratory Database, which collects all biochemical analyses for hospital laboratories. Baseline sCr was defined as the lowest sCr in the year before cancer diagnosis. We compared this value to the highest sCr on record during the first year following cancer diagnosis to identify those who experienced an AKI. Results: Median age for the cohort was 68.6 years, 50.9% were men, and the most common cancer sites were lung (14.2%), breast (13.7%), prostate (9.8%), colon (9.6%), rectum (5.1%), and bladder (6.3%). During the first year, 973 (22.0%) members of the cohort experienced an AKI, corresponding to an overall incidence rate of 326 per 1,000 person-years (95% confidence interval (CI) 306–347). Incidence was highest among patients aged 80 years or older (531 per 1,000 person-years, 95% CI 464–606) and in those with cancer of the liver (1,221, 95%CI 676–2,205), pancreas (1,472, 95%CI 1,130–1,917), or kidney (1,254, 95%CI 974–1,616), or with multiple myeloma (855, 95%CI 538–1,356). Conclusions: To protect against AKI, we must first identify those at risk. Our study showed that over 20% of cancer patients may experience acute kidney injury in the first year after diagnosis. Older patients and those with cancer of the liver, pancreas, or kidney, or with multiple myeloma are especially at risk for AKI.

[Table: see text]

Risk of acute renal failure among breast cancer patients and chemotherapy treatment of breast cancer patients with a history of renal insufficiency in a commercially-insured population in the United States

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Background: Risk of acute renal failure (ARF) among breast cancer (BC) patients may increase with nephrotoxic chemotherapy and other exposures, but this risk is not well characterized. Furthermore, among patients who present with renal insufficiencies (RI) at cancer diagnosis, subsequent treatment patterns are not well described. Methods: We performed a retrospective cohort study using a large national commercial claims database. The cohort included all women diagnosed with BC from 2000 to 2007 who were 18–64 years at diagnosis with no history of cancer (n=13,296). We defined a diagnosis of BC as at least one inpatient or two outpatient claims more than 30 days apart with an ICD-9 code of 174. Among patients with no history of RI (n=13,150), we calculated the cumulative incidence (CI) of ARF_the proportion with at least one inpatient or two outpatient claims with an ICD-9 code of 584 or 586 in the first year following cancer diagnosis. Treatment for BC patients with a history of RI (n=146) was also assessed. Results: Among BC patients with no history of RI, 0.3% were diagnosed with ARF within a year after cancer diagnosis. The CI of ARF was higher in patients with metastases: 0.7% for any metastasis, 2.3% for bone metastasis, and 0.1% for no metastasis. The CI of ARF among patients undergoing radiation or mastectomy was similar to the overall rate (0.3%) but was higher in patients receiving nephrotoxic chemotherapy (1.0%) or intravenous bisphosphonates (IV BPs) (2.1%). The CI of ARF was higher in patients with congestive heart failure (1.4%), diabetes (0.9%), and/or hypertension (0.8%) at cancer diagnosis compared to patients without these comorbidities (0.2%). Among BC patients with a history of RI, 7.5% were administered nephrotoxic chemotherapy, 30.1% received potentially nephrotoxic chemotherapy, and 1.4% were given IV BPs. Conclusions: Breast cancer patients who present with comorbidities, develop metastases, or are given nephrotoxic chemotherapy or IV bisphosphonates are at higher risk of acute renal failure in the first year after breast cancer diagnosis. More research is warranted on the treatment of breast cancer patients with a history of renal insufficiency.

[Table: see text]

The prognostic significance of bone metastases and skeletal-related events (SREs) in prostate cancer survival: A population-based historical cohort study in Denmark (1999–2007)

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Background: Common among advanced prostate cancer patients, bone metastases indicate cancer progression and poor prognosis but few studies have quantified their influence on patient survival, particularly in the presence of subsequent skeletal-related complications. We therefore sought to examine this in a large population-based cohort of prostate cancer patients. Methods: Using data from the Danish National Patient Registry (covering all Danish hospitals), we studied 23,087 patients diagnosed with prostate cancer between 1999 and 2007, with follow-up through April 2008 (median follow-up: 2.2 years). We estimated the incidence of bone metastases following cancer diagnosis and the subsequent occurrence of SREs (radiation and surgery to the bone, fracture, spinal cord compression). We then computed and compared survival for three prostate cancer subgroups - no bone metastases, bone metastases, and bone metastases with SREs - using Kaplan-Meier and multivariate Cox proportional hazards models. Results: Across the study period, 14% (n = 3,261) of the prostate cancer patients developed bone metastases: 6.8% (n = 1,570) had bone metastases and no SRE and 7.3% (n = 1,691) had both bone metastases and at least one SRE (radiation to the bone was most frequent). One-year survival was lowest for prostate cancer patients with bone metastases and SREs (40%) compared to the groups with no bone metastases (87%) and with bone metastases but no SREs (47%). Similarly, after adjusting for age and the presence of comorbidities, short-term prognosis was poorest in patients with both bone metastases and SREs: compared to prostate cancer patients with no bone metastases, the 1-year mortality rate was 6.7 times greater for those with bone metastases and SREs (95% confidence interval (CI): 6.0–7.6) versus just 4.7 times higher in those with only bone metastases (95% CI: 4.3–5.2). Less than 1% of prostate cancer patients who developed bone metastases and suffered any SRE survived beyond five years. Conclusions: Although the presence of bone metastases confers a short-term prognosis in prostate cancer patients, survival is even poorer for patients who also experience skeletal-related complications.

[Table: see text]

Parkinson's disease and other basal ganglia or movement disorders in a large nationwide cohort of Swedish welders

INTRODUCTION

Although it has been hypothesised that metal welding and flame cutting are associated with an increased risk for Parkinson's disease due to manganese released in the welding fume, few rigorous cohort studies have evaluated this risk.

METHODS

The authors examined the relation between employment as a welder and all basal ganglia and movement disorders (ICD-10, G20-26) in Sweden using nationwide and population based registers. All men recorded as welders or flame cutters (n = 49,488) in the 1960 or 1970 Swedish National Census were identified and their rates of specific basal ganglia and movement disorders between 1964 and 2003 were compared with those in an age and geographical area matched general population comparison cohort of gainfully employed men (n = 489,572).

RESULTS

The overall rate for basal ganglia and movement disorders combined was similar for the welders and flame cutters compared with the general population (adjusted rate ratio (aRR) = 0.91 (95% CI 0.81 to 1.01). Similarly, the rate ratio for PD was 0.89 (95% CI 0.79 to 0.99). Adjusted rate ratios for other individual basal ganglia and movement disorders were also not significantly increased or decreased. Further analyses of Parkinson's disease by attained age, time period of follow up, geographical area of residency, and educational level revealed no significant differences between the welders and the general population. Rates for Parkinson's disease among welders in shipyards, where exposures to welding fumes are higher, were also similar to the general population (aRR = 0.95; 95% CI 0.70 to 1.28).

CONCLUSION

This nationwide record linkage study offers no support for a relation between welding and Parkinson's disease or any other specific basal ganglia and movement disorders.

A cohort study of antihypertensive treatments and risk of renal cell cancer

We studied 335 682 county residents, of whom 113 298 had been prescribed antihypertensive treatment (AHT), in the period 1989–2002 in North Jutland County, Denmark to examine the relation between different AHTs and the risk of renal cell carcinoma (RCC). An internal comparison was performed among the different classes of AHT users with users of beta blockers as the reference, in order to address potential confounding and bias. The average follow-up was 10 years (range 0–13). Use of any AHT was associated with RCC (relative rate (RR)=1.6, 95% confidence interval (CI) 1.3–1.9) compared with nonusers in the general population. Specific classes of AHTs were nonsignificantly associated with RCC, but compared with users of beta blockers, the numbers observed were close to expectation. Analyses by duration of follow-up and number of prescriptions revealed no clear trends for any antihypertensive agent and after 5-years of follow-up, the RRs for all classes of AHT decreased. The elevated RRs for RCC among users of AHTs compared with the general population are unlikely to be causal, but rather reflect confounding due to failure to control for pre-existing hypertension, and protopathic bias, due to the presence of hypertension as an early sign of kidney disease.

Acetaminophen, aspirin, and chronic renal failure

BACKGROUND

Several epidemiologic studies have demonstrated an association between heavy consumption of nonnarcotic analgesics and the occurrence of chronic renal failure, but it is unclear which is the cause and which is the effect

METHODS

In a nationwide, population-based, case-control study of early-stage chronic renal failure in Sweden, face-to-face interviews were conducted with 926 patients with newly diagnosed renal failure and 998 control subjects, of whom 918 and 980, respectively, had complete data. We used logistic-regression models to estimate the relative risks of disease-specific types of chronic renal failure associated with the use of various analgesics

RESULTS

Aspirin and acetaminophen were used regularly by 37 percent and 25 percent, respectively, of the patients with renal failure and by 19 percent and 12 percent, respectively, of the controls. Regular use of either drug in the absence of the other was associated with an increase by a factor of 2.5 in the risk of chronic renal failure from any cause. The relative risks rose with increasing cumulative lifetime doses, rose more consistently with acetaminophen use than with aspirin use, and were increased for most disease-specific types of chronic renal failure. When we disregarded the recent use of analgesics, which could have occurred in response to antecedents of renal disease, the associations were only slightly attenuated

CONCLUSIONS

Our results are consistent with the existence of exacerbating effects of acetaminophen and aspirin on chronic renal failure. However, we cannot rule out the possibility of bias due to the triggering of analgesic consumption by predisposing conditions.

Nationwide study of cancer risk among hip replacement patients in Sweden

BACKGROUND

Orthopedic implants and their fixatives contain materials with carcinogenic potential. Whether these implants are linked to subsequent cancer development remains unknown, mainly because large-scale, long-term follow-up data are scarce.

METHODS

We conducted a nationwide cohort study in Sweden to examine cancer incidence among 116,727 patients who underwent hip replacement surgery during the period from 1965 through 1994. Through record linkage to the Swedish Cancer Register, we identified all incident cancers through 1995 in this population (693,954 person-years of observation). For each cancer type, the observed number of cases was divided by that expected in the general Swedish population to produce standardized incidence ratios (SIRs).

RESULTS

Relative to the general population, the cohort had no overall cancer excess (SIR = 1.01; 95% confidence interval [CI] = 0.99 to 1.03). However, we observed elevated SIRs for prostate cancer (SIR = 1.16; 95% CI = 1.11 to 1.22) and melanoma (SIR = 1.15; 95% CI = 1.01 to 1.30) and a reduction in stomach cancer risk (SIR = 0.83; 95% CI = 0.75 to 0.92). Long-term follow-up (>or=15 years) revealed an excess of multiple myeloma (SIR = 1.86; 95% CI = 1.01 to 3.11) and a statistically nonsignificant increase in bladder cancer (SIR = 1.42; 95% CI = 0.98 to 1.99). There was no material increase in risk for bone or connective tissue cancer for either men or women in any follow-up period.

CONCLUSIONS

In this, the largest study to date, hip implant patients had similar rates of most types of cancer to those in the general population. Although the excesses of melanoma, multiple myeloma, and prostate and bladder cancers may be due to chance, confounding, or detection bias and should be interpreted cautiously, they warrant further investigation because of the ever-increasing use of hip implants at younger ages.

Cancer mortality in relation to environmental chromium exposure

From the 1950s to the 1980s, hexavalent chromium compounds were used as additives at certain water-cooling towers at three southern California gas compressor facilities. Claims of potential residential chromium exposure prompted the examination of age-adjusted mortality rates during 1989 to 1998 for lung cancer, all cancer, and all deaths for neighborhoods near versus distant from the plants. Differences in the rates between areas tended to be small and not statistically significant. The only significant difference was a lower, rather than higher, rate of total cancer among women in the potentially exposed areas. Study limitations preclude a definitive assessment of risk, but similar to previous investigations of cancer in relation to environmental chromium exposure in other locations, this study found no evidence of a cancer hazard among residents living near these California gas compressor facilities.

Familial risk of pancreatic cancer

BACKGROUND

Pancreatic cancer is the fifth leading cause of cancer-related mortality in the United STATES: Although smoking and age are known risk factors for pancreatic cancer, several case reports and case-control studies have suggested that there is also a familial risk. We evaluated whether a family history of pancreatic cancer increases the risk of pancreatic cancer in first-degree relatives and whether smoking and younger age at cancer diagnosis further increase this risk.

METHODS

We conducted in-person interviews with 247 patients ("case probands") with pancreatic cancer and 420 population-based control probands to collect risk factor data and pancreatic cancer family history for 1816 first-degree relatives of the case probands and 3157 first-degree relatives of the control probands. We analyzed the data by unconditional logistic regression models, with adjustment for correlated data by use of generalized estimating equations. All statistical tests were two-sided.

RESULTS

A positive family history of pancreatic cancer (i.e., being related to a case proband) or ever-smoking cigarettes approximately doubled the risk of pancreatic cancer (relative risk [RR] = 2.49; 95% confidence interval [CI] = 1.32 to 4.69; RR = 2.04; 95% CI = 1.09 to 3.83, respectively). The RR increased to 8.23 (95% CI = 2.18 to 31.07) for relatives who ever smoked and were related to a case proband who was diagnosed before age 60 years.

CONCLUSION

Routine questioning of patients about a family history of pancreatic cancer, the age of onset of this cancer in their relatives, and the patient's smoking status may identify individuals at high risk of pancreatic cancer. Future research exploring the genetic and environmental interactions associated with the risk of pancreatic cancer is critically important.

Comparison of surrogate with self-respondents regarding medical history and prior medication use

BACKGROUND

The self-report of medical history and medication use is a common feature of epidemiological research.

METHODS

In a unique re-interview study, we evaluated the concordance of medical conditions and past medication use reported in two similar interviews 5 years apart.

RESULTS

In 196 re-interviews with the subjects themselves, and in 107 with next-of-kin of subjects who died after the first interview, agreement was good or excellent (kappa > or =0.40) for 90% (9/10) of the conditions asked about in the personal medical history for both next-of-kin and self-respondents. Agreement was excellent (kappa >0.75) for two conditions, high blood pressure and hysterectomy, among self-respondents. Self- and surrogate respondents also showed similar reproducibility for prescription medications, but next-of-kin respondents tended to have poor agreement (kappa <0.40) for over-the-counter (OTC) medications such as antacids, antihistamines, and analgesics. Next-of-kin also less reliably reported a family history of cancer. When analyses were stratified by type of surrogate respondent, concordance between the two interviews was generally higher for spouses than for other surrogate respondents.

CONCLUSIONS

This research demonstrates that personal medical history and prescription medication use may be as reliably reported by next-of-kin as self-respondents, but suggests that additional information may be needed to validate measures of OTC medication use and family history of cancer for next-of-kin respondents, possibly through the review of hospital records.

Risks of fracture of Björk-Shiley 60 degree convexo-concave prosthetic heart valves: long-term cohort follow up in the UK, Netherlands and USA

BACKGROUND AND AIM OF THE STUDY

Approximately 82,000 Björk-Shiley convexo-concave (BSCC) 60 degree prosthetic heart valves were implanted in patients worldwide between 1979 and 1986. Outlet strut fractures (OSF) of some of the valves were first reported shortly after their introduction. Here, the determinants of OSF are examined, and the between-country variation and long-term risk are assessed.

METHODS

Cohorts of patients in the UK, Netherlands and USA with 15,770 BSCC 60 degree heart valves were followed up to 18 years for the occurrence of OSF.

RESULTS

Crude rates of OSF were highest in the UK (0.18% per year), intermediate in the Netherlands (0.13%), and lowest in the USA (0.06%), although risk factor adjustment reduced the inter-country differences. Furthermore, in the UK and Netherlands, OSF rates (particularly for mitral valves) declined with time since implantation, and between-country differences were considerably diminished 10 or more years post implantation. The risk of OSF decreased steadily with advancing patient age. Fracture rates were lower among women than men, and also varied significantly with valve size and position and OSF status of other valves in the same shoporder.

CONCLUSION

This long-term follow up of BSCC 60 degree heart valve patients indicates that risk factors for valve fracture are generally similar in the UK, Netherlands and USA. It also identifies a strong association between fracture risk and age, newly reveals gender-related differences, and shows that the risk of valve fracture persisted, albeit at a reduced rate, into the 1990s.

Offspring health risk after cosmetic breast implantation in Sweden

Case reports have suggested that children born to women with silicone breast implants may have an excess risk of rheumatic disease and/or esophageal disorders. In Sweden, the authors conducted a retrospective cohort study of 5,874 children born to women with cosmetic breast implants and 13,274 children born to women who had breast reduction surgery. Using national registers, they computed hospitalization rates for rheumatic and esophageal disorders, incidence rates for cancer, and prevalence rates for congenital malformations and perinatal death. Relative to children of women who had breast reduction surgery, children born to women who had cosmetic breast implants were not at excess risk of rheumatic disease (relative risk [RR] = 1.1; 95% confidence interval [95% CI], 0.2-5.3), esophageal disorders (RR = 1.0; 95% CI, 0.7-1.6), cancer (RR = 0.3; 95% CI, 0.0-2.5), congenital malformations in total (RR = 1.0; 95% CI, 0.6-1.5), or specifically involving the digestive organs (RR = 0.5; 95% CI, 0.2-1.3) or perinatal death (RR = 0.9; 95% CI, 0.5-1.8). The rates of these health outcomes among children born after a mother's implant surgery were also not significantly higher than among children born before a mother's implant surgery. This study provides no evidence that certain hypothesized health outcomes are more likely among the children of women with cosmetic breast implants.

Self-reported symptoms among women after cosmetic breast implant and breast reduction surgery

A retrospective cohort study was performed in Sweden to evaluate the possibility that an individual symptom or constellation of illness symptoms related to silicone occurs in women after breast implant surgery. A random sample (n = 2500) of all women in the Swedish national implant registry who underwent breast augmentation surgery with alloplastic breast implants during the years 1965 through 1993 was compared with a sample (n = 3500) of women who underwent breast reduction surgery during the same period, frequency matched to the implant patients for age and calendar year at the time of surgery. In total, 65 percent of the breast implant patients (n = 1546) and 72 percent of the breast reduction patients (n = 2496) completed a self-administered questionnaire covering 28 rheumatologic and other symptoms and lifestyle and demographic factors. Practically all of the 28 symptoms inquired about were reported more often by women in the breast implant cohort, with 16 (57 percent) significantly more common in breast implant recipients. In contrast, few significant differences or consistent patterns were observed in the length of time since the implant and in the type (silicone or saline) or volume of the implant. Although women with breast implants report a multitude of symptoms more often than women who have breast reduction surgery, the lack of specificity and absence of dose-response relationships suggest that the excess of reported symptoms is not causally related to cosmetic implants.

Local complications and subsequent symptom reporting among women with cosmetic breast implants

Epidemiologic studies have found no association between breast implants and cancer or well-defined connective tissue diseases. However, women with cosmetic breast implants continue to report specific as well as nonspecific physical and psychological symptoms after receiving their implants. In an attempt to determine whether local complications of implantation may contribute to this excess of symptom reporting, the authors studied a large cohort of women in Sweden with cosmetic breast implants (n = 1280) and a comparison cohort of women who had cosmetic breast reduction surgery (n = 2211). Both groups of women had operations between 1969 and 1996. Medical record reviews of local complications revealed that approximately 31 percent of the women with cosmetic breast implants had an implant change, implant leakage, or a capsulotomy. Capsulotomies occurred more often in women who were age 35 or older at the time of the operation, had ever smoked, and had implants with a smooth surface. On self-administered questionnaires, symptoms were reported more often by the women who had implants regardless of whether they had local complications. Twenty of the 28 symptoms occurred more frequently among women with local complications and breast implants, compared with the women in the breast reduction comparison group or the women with breast implants but no local complications. This study suggests that local complications, particularly capsular contractures as indicated by capsulotomy, may be an important factor to consider when studying symptom reporting among women with breast implants.

Characteristics of women with cosmetic breast augmentation surgery compared with breast reduction surgery patients and women in the general population of Sweden

To determine whether women with cosmetic breast implants have distinct demographic, lifestyle, and reproductive characteristics that put them at increased risk for subsequent morbidity, the authors compared 1,369 such women to 2,211 women who had undergone breast reduction surgery, and to a random sample of 49,262 women from the general population of Sweden. Information was collected through self-administered questionnaires, and comparisons were made using the prevalence odds ratio. Women with cosmetic breast implants were significantly (p <0.05) more likely to be current smokers, have a lower body mass index, have had a prematurely terminated pregnancy (induced abortion or miscarriage), and have had fewer live births than either women who underwent breast reduction or women from the general population. Type of implant (silicone gel or saline) did not modify the associations. Regardless of the comparison group used, studies of the health effects of breast implants need to consider that women who undergo cosmetic breast implantation have certain distinct characteristics.

Exposure assessment for a large epidemiological study of aircraft manufacturing workers

Methods were developed to assess exposure to a wide variety of chemicals for nearly 80,000 workers involved in manufacturing aircraft since 1928. The facilities, now closed, consisted of four major plants, over 200 buildings, and a changing workforce during 60 years of operation. To access chemical exposures by specific jobs and calendar years, we reviewed complete work histories, examined detailed job descriptions available going back to 1940, interviewed long-term employees, conducted walk-through visits of aircraft manufacturing plants, reviewed comprehensive environmental assessment reports and industrial hygiene surveys on the facilities, and built on experience gained in previous studies of the aircraft industry. Using computer-based imaging systems, we examined and evaluated the complete work histories found on service record cards for the cohort and abstracted detailed information on all jobs held among the factory workers who had been employed for at least one year. Jobs were classified into one of three exposure categories related to the use of specific chemicals: routine, intermittent, and none, and these classifications were subsequently used in the epidemiological analyses. The approach to exposure assessment began with the most general categorization of employees (i.e., all workers) and then became progressively more specific, that is, factor workers, job families (similar activities), job titles, and jobs with chemical usage (exposure potential). Because exposure surveys were limited or absent during the early years of plant operations, we did not assign quantitative measures of exposure to individual job activities. Instead, we used as our exposure metric, the length of time spent in jobs with potential exposure to the chemical. Important occupational exposures included chromate-containing compounds such as used in paint primers, trichloroethylene and perchloroethylene used as vapor-state degreasing solvents, and a broad range of other solvents.

Connective tissue disease and other related rheumatic conditions among patients with finger and hand and temporomandibular joint prostheses in Denmark

OBJECTIVE

To determine if finger and hand joint prostheses or temporomandibular joint (TMJ) implants may be involved in the initiation of specific connective tissue diseases (CTD), a nationwide cohort in Denmark was followed prospectively to evaluate rates of CTD after receiving these implants.

METHODS

Danish patients with finger and hand joint implants (n = 562) or TMJ implants (n = 351) were identified and followed for subsequent hospitalizations. Observed numbers of hospitalizations due to CTD were compared with expected numbers based on national CTD hospitalization rates. To avoid confounding by indication, patients with a hospital discharge diagnosis of a CTD prior to prosthetic surgery were excluded from the cohort.

RESULTS

After 4142 person-years of followup in the finger and hand joint cohort, 9 hospitalizations due to CTD were found [standard hospitalization rate (SHR) = 1.5; 95% CI 0.7-2.9]. The TMJ cohort had 1500 person-years of followup and 2 hospitalizations due to CTD (SHR = 1.3; 95% CI 0.2-4.5).

CONCLUSION

This is the first cohort study to examine the relations between these implants and CTD. Although the number of events was small, this systematic national study revealed no significant or large increase in risk of CTD after finger and hand joint implants or TMJ implants.

Comparison of surrogate with self-respondents for occupational factors

Accurate assessment of occupational history is critical in case-control studies of disease risk associated with employment. However, in some studies of rapidly fatal diseases, a surrogate or next of kin is interviewed rather than the study subject. In a unique re-interview study of subjects from a community-based case-control study originally interviewed 5 years earlier, we evaluated the level of agreement between (1) subjects and their surrogates on re-interview among those who had died since the first interview, and (2) subjects themselves and their responses at re-interview among those still living (to use as a comparison) regarding work history and specific occupational exposures. For employment start and stop dates, number of years worked, and number of jobs reported in the 1980 interview, exact agreement was poor for surrogate respondents and for self-respondents in the re-interview, with percentages ranging from 4% to 40%. Agreement was similar for surrogates and self-respondents for job and industry worked the longest, but percent of agreement among surrogates was significantly lower than among the self-respondents for job and industry worked last. Five (28%) of the kappa values for the industry in which the subject worked had high agreement (kappa > 0.75) for self-respondents and surrogates. None of the kappa statistics for materials handled by subjects in their jobs had high agreement, and 57% of the kappa statistics had poor agreement (kappa 0.0 to 0.39). This study suggests that occupational histories obtained by interview are poorly reproduced, and existing methods may need improvement to collect reliable occupational data. Further, the findings indicate that caution should be exercised when creating a job-exposure matrix based on such data.

A cohort mortality study among gas generator utility workers

An earlier cohort study tracked the mortality experience through 1988 of male employees at five utility companies in the United States. Workers employed by the Pacific Gas and Electric Company (PG&E) were part of that study, but results for PG&E employees overall or for those involved in gas generator plant operations where hexavalent chromium compounds were used in open and closed systems from the 1950s to early 1980s were not reported. To evaluate risk of lung cancer and other diseases, a cohort of 51,899 PG&E male workers was followed for mortality from 1971 through 1997. Observed numbers of deaths were compared with those expected based on rates in the general California population, with standardized mortality ratios (SMR) and corresponding 95% confidence intervals (CI) calculated for the total cohort and for subsets defined by potential for gas generator plant exposure. A total of 10,591 deaths were observed, a number significantly less than expected (SMR, 0.89; 95% CI, 0.87 to 0.91). No significant excesses of total or specific cancers were observed, with SMR typically near or below 1.0. Lung cancer mortality in the entire cohort was close to expected (SMR, 0.98; 95% CI, 0.92 to 1.05), with no excess detected among persons who worked (SMR, 0.81; 95% CI, 0.35 to 1.60) or trained (SMR, 0.57; 95% CI, 0.12 to 1.67) at gas generator facilities. Furthermore, risk of lung cancer did not increase with increasing duration of employment or time since hire. The study thus provides no evidence that occupational exposures at PG&E facilities resulted in increased risk of lung cancer or any other cause of death. The results indicate that any chromium exposures were of insufficient magnitude to result in increased risk of lung cancer.

Mortality among aircraft manufacturing workers

OBJECTIVES

To evaluate the risk of cancer and other diseases among workers engaged in aircraft manufacturing and potentially exposed to compounds containing chromate, trichloroethylene (TCE), perchloroethylene (PCE), and mixed solvents.

METHODS

A retrospective cohort mortality study was conducted of workers employed for at least 1 year at a large aircraft manufacturing facility in California on or after 1 January 1960. The mortality experience of these workers was determined by examination of national, state, and company records to the end of 1996. Standardised mortality ratios (SMRs) were evaluated comparing the observed numbers of deaths among workers with those expected in the general population adjusting for age, sex, race, and calendar year. The SMRs for 40 cause of death categories were computed for the total cohort and for subgroups defined by sex, race, position in the factory, work duration, year of first employment, latency, and broad occupational groups. Factory job titles were classified as to likely use of chemicals, and internal Poisson regression analyses were used to compute mortality risk ratios for categories of years of exposure to chromate, TCE, PCE, and mixed solvents, with unexposed factory workers serving as referents.

RESULTS

The study cohort comprised 77,965 workers who accrued nearly 1.9 million person-years of follow up (mean 24.2 years). Mortality follow up, estimated as 99% complete, showed that 20,236 workers had died by 31 December 1996, with cause of death obtained for 98%. Workers experienced low overall mortality (all causes of death SMR 0.83) and low cancer mortality (SMR 0.90). No significant increases in risk were found for any of the 40 specific cause of death categories, whereas for several causes the numbers of deaths were significantly below expectation. Analyses by occupational group and specific job titles showed no remarkable mortality patterns. Factory workers estimated to have been routinely exposed to chromate were not at increased risk of total cancer (SMR 0.93) or of lung cancer (SMR 1.02). Workers routinely exposed to TCE, PCE, or a mixture of solvents also were not at increased risk of total cancer (SMRs 0.86, 1.07, and 0.89, respectively), and the numbers of deaths for specific cancer sites were close to expected values. Slight to moderately increased rates of non-Hodgkin's lymphoma were found among workers exposed to TCE or PCE, but none was significant. A significant increase in testicular cancer was found among those with exposure to mixed solvents, but the excess was based on only six deaths and could not be linked to any particular solvent or job activity. Internal cohort analyses showed no significant trends of increased risk for any cancer with increasing years of exposure to chromate or solvents.

CONCLUSIONS

The results from this large scale cohort study of workers followed up for over 3 decades provide no clear evidence that occupational exposures at the aircraft manufacturing factory resulted in increases in the risk of death from cancer or other diseases. Our findings support previous studies of aircraft workers in which cancer risks were generally at or below expected levels.

Cancer risk among patients with finger and hand joint and temporo-mandibular joint prostheses in Denmark

The use of artificial joint implants has risen greatly over the past years. However, few investigations of the cancer risk associated with implants have been performed. We investigated cancer risk in patients with finger and hand joint and temporo-mandibular (TMJ) joint implants. A nationwide cohort in Denmark of patients with finger and hand joint prostheses (n = 858) or TMJ implants (n = 389) was followed from January 1, 1977, to December 31, 1995, to evaluate any potential cancer risks subsequent to receiving these implants. Standardized incidence ratios (SIRs) for all cancers were 1.0 (95% CI = 0.8-1.2) for the finger and hand joint cohort and 1.1 (95% CI = 0.8-1.7) for the TMJ cohort. A significant risk for non-Hodgkin's lymphoma was found in the finger and hand joint cohort (SIR = 3.8, 95% CI = 1.5-7.8). When the finger and hand joint cohort was stratified by diagnosis of rheumatoid arthritis, the excess risk was seen only in the group with rheumatoid arthritis. This is consistent with past studies, which have found an association between rheumatoid arthritis and non-Hodgkin's lymphoma. Our results provide evidence that the cancer risk for patients with finger and hand joint prostheses and TMJ implants is similar to that for the general population.

A case-control study of self-reported exposures to pesticides and pancreas cancer in southeastern Michigan

A case-control study of pancreas cancer in residents, aged 30-79 years, of 18 counties in southeastern Michigan was conducted to investigate the risks of exposure to DDT and related materials in the general population. Sixty-six people with cytologically diagnosed pancreas cancer were identified using 7 participating hospitals in metropolitan Detroit and Ann Arbor. One hundred and thirty-one controls were frequency-matched to the cases on age, sex, ethicity and county of residence by random-digit dialing. All study participants were administered a questionnaire to assess life-time exposure to pesticides from both environmental and occupational sources, family history of cancer, past medical history, smoking history and demographic information. A statistically significant increased risk was found for self-reported exposure to ethylan (1,1-dichloro-2,2-bis(4-methoxyphenyl) ethane). Increased odds ratios were observed for self-reported exposures to chloropropylate and DDT, as well as for the summary group of organochlorine pesticides which included all of these materials, though these associations were not significant.

Comparison of laboratory test frequency and test results between African-Americans and Caucasians with diabetes: opportunity for improvement. Findings from a large urban health maintenance organization

OBJECTIVE

To compare African-American and Caucasian patients with preexisting diabetes in a health maintenance organization (HMO) on: 1) frequency with which they received a subset of recommended laboratory tests according to the American Diabetes Association (ADA) consensus guidelines and 2) the results of laboratory test values (glycosylated hemoglobin, cholesterol, and creatinine).

RESEARCH DESIGN AND METHODS

A cross-sectional study of 2,312 HMO members with diabetes continuously enrolled during 1991 was conducted using computerized medical record and billing data. Receipt of the ADA recommended tests for glycosylated hemoglobin, cholesterol, and creatinine was compared between African-Americans and Caucasians, stratified by insulin requirements. In addition, group comparisons were made based on the laboratory test results.

RESULTS

Less than 20 percent of all subjects received the recommended number of ADA tests. This did not differ by race except for creatinine and cholesterol testing in insulin users only, where African-Americans had more tests. On average, after adjusting for covariates, African-Americans had significantly higher glycosylated hemoglobin and creatinine laboratory values. Both groups had elevated cholesterol values.

CONCLUSIONS

The opportunity exists to improve the process of care for both African-Americans and Caucasians with diabetes in an HMO setting. The need to improve glycosylated hemoglobin results and subsequently limit complications is especially pressing among the African-American population.