Acetaminophen, aspirin and progression of advanced chronic kidney disease

BACKGROUND

Although many studies have investigated the possible association between analgesic use (acetaminophen and aspirin) and the development of chronic kidney disease (CKD), the effect of analgesics on the progression of established CKD of any cause has not yet been investigated.

METHODS

In this population-based Swedish cohort study, we investigated the decline over 5-7 years in estimated glomerular filtration rate (eGFR) among 801 patients with incident, advanced CKD (serum creatinine >3.4 mg/dL for men, >2.8 mg/dL for women for the first time) and with different analgesic exposures. Lifetime analgesic use and current regular use were ascertained through in-person interviews at inclusion while data on analgesic use during the follow-up was abstracted from the medical records at the end of the study period. A linear regression slope, based on their eGFR values during the follow-up, provided a summary of within-individual change. In the final multivariate analyses, a linear mixed effects model was implemented to assess the relation of analgesic use and change in eGFR over time.

RESULTS

The progression rate for regular users of acetaminophen was slower than that for non-regular users (regular users progressed 0.93 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.03, 1.8). For regular users of aspirin, the progression rate was significantly slower than that for non-regular users (regular users progressed 0.80 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.1, 1.5). Different levels of lifetime cumulative dose of acetaminophen and aspirin did not significantly affect the progression rate.

CONCLUSION

We suggest that single substance acetaminophen and aspirin may be safe to use by patients with diagnosed advanced CKD stage 4-5 without an adverse effect on the progression rate of the disease.

Excess Mortality From Suicide and Other External Causes of Death Among Women With Cosmetic Breast Implants

An increased rate of suicide among women with cosmetic breast implants has been consistently reported in the epidemiologic literature. We extended by 8 years the follow-up of our earlier mortality study of a nationwide cohort of 3527 Swedish women with cosmetic breast implants to examine in greater detail suicide and other causes of death. The number of deaths observed among these women was compared with the number expected among the age- and calendar-period-matched general female population of Sweden. Women with breast implants were followed for over 65,000 person-years, with a mean follow-up of 18.7 years (range, 0.1-37.8 years). Overall, 175 deaths occurred among women with breast implants versus 133.4 expected (standardized mortality ratio (SMR) = 1.3; 95% confidence interval [CI], 1.1-1.5). Among women with implants, we observed statistically significant 3-fold excesses of suicide (SMR, 3.0; 95% CI, 1.9-4.5) and deaths from alcohol or drug dependence (SMR, 3.1; 95% CI, 1.0-7.3), as well as an excess of deaths from accidents and injuries consistent with substance abuse or dependence. The increased risk of suicide was not apparent until 10 years after implantation. Deaths from cancer overall were close to expectation (SMR, 1.1; 95% CI, 0.8-1.4). Women with cosmetic implants had elevated SMRs for lung cancer and chronic respiratory disease. There was no excess of breast cancer mortality. The excess of deaths from suicides, drug and alcohol abuse and dependence, and other related causes suggests significant underlying psychiatric morbidity among these women. Thus, screening for pre-implant psychiatric morbidity and post-implant monitoring among women seeking cosmetic breast implants may be warranted.

A Nationwide Study of Connective Tissue Disease and Other Rheumatic Conditions Among Danish Women With Long-Term Cosmetic Breast Implantation

PURPOSE

Numerous epidemiologic studies have demonstrated that breast implants are not associated with connective tissue diseases (CTDs). However, many CTDs are rare, and continued follow-up of women with breast implants is warranted.

METHODS

We extended by 5 years the follow-up of our earlier population-based cohort study of Danish women with cosmetic breast implants (n = 2761) and comparison groups of women with other types of cosmetic surgery (n = 8807). All women were followed from January 1977 through December 2001. Hospitalization and outpatient data for CTD and ill-defined and other rheumatic conditions in the implant and comparison groups were compared with those in the general Danish population. Additionally, CTDs and fibromyalgia were confirmed through medical chart review, and direct comparisons of the breast implant cohort with the comparison cohort were performed.

RESULTS

When compared with general population rates, CTDs were not statistically significantly elevated in either the implant or the comparison cohorts. However, unspecified rheumatism was similarly increased in the implant (standardized rate ratio = 1.9; 95% confidence interval = 1.6 to 2.2) and comparison (standardized rate ratio = 1.5; 95% confidence interval = 1.4 to 1.7) cohorts. In analyses of diagnoses validated by chart review, women with cosmetic breast implants compared with those having other types of plastic surgery or consultation for plastic surgery had no statistically significant excess for any specific confirmed CTD or combined CTDs (hazard ratio = 1.3; 95% CI = 0.9 to 1.9). In addition, there was no relation between breast implants and confirmed fibromyalgia (hazard ratio = 1.2; 95% CI = 0.6 to 2.1).

CONCLUSIONS

This extension of our earlier cohort study further supports the consensus of epidemiologic research that breast implants are unrelated to the development of CTD.

Mortality among Rocketdyne workers who tested rocket engines, 1948-1999

OBJECTIVE

The objective of this study was to evaluate potential health risks associated with testing rocket engines.

METHODS

A retrospective cohort mortality study was conducted of 8372 Rocketdyne workers employed 1948 to 1999 at the Santa Susana Field Laboratory (SSFL). Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) were calculated for all workers, including those employed at specific test areas where particular fuels, solvents, and chemicals were used. Dose-response trends were evaluated using Cox proportional hazards models.

RESULTS

SMRs for all cancers were close to population expectations among SSFL workers overall (SMR = 0.89; CI = 0.82-0.96) and test stand mechanics in particular (n = 1651; SMR = 1.00; CI = 0.86-1.16), including those likely exposed to hydrazines (n = 315; SMR = 1.09; CI = 0.75-1.52) or trichloroethylene (TCE) (n = 1111; SMR = 1.00; CI = 0.83-1.19). Nonsignificant associations were seen between kidney cancer and TCE, lung cancer and hydrazines, and stomach cancer and years worked as a test stand mechanic. No trends over exposure categories were statistically significant.

CONCLUSION

Work at the SSFL rocket engine test facility or as a test stand mechanic was not associated with a significant increase in cancer mortality overall or for any specific cancer.

A cohort study of antihypertensive medication use and breast cancer among Danish women

BACKGROUND

It has been suggested that specific antihypertensive medications (AHT) may either increase or decrease breast cancer risk.

METHODS

We studied breast cancer incidence among 49,950 women in North Jutland, Denmark in order to determine if breast cancer risk is associated with specific classes of AHT use. Poisson regression analyses were used to calculate rate ratios for ever or exclusive use of each class of AHT, number of prescriptions for AHT, and years of follow-up.

RESULTS

There was no statistically significant association between ever use of any AHT overall (RR = 0.95; 95% CI = 0.81-1.10) or any specific class of AHT (diuretics, beta blockers, calcium channel blockers (CCBs), angiotensin converting enzyme (ACE) inhibitors, and angiotensin II antagonists) and breast cancer.

CONCLUSIONS

This study should offer further reassurance to women currently using AHT that their medication use is unlikely related to breast cancer risk.

Long-Term Cancer Risk Among Swedish Women With Cosmetic Breast Implants: An Update of a Nationwide Study

Epidemiologic evidence does not support a consistently increased cancer risk among women with cosmetic breast implants, but few studies have assessed risk beyond 15 years. Swedish women who underwent cosmetic breast implantation for the first time between January 1, 1965, and December 31, 1993 (N = 3486), were followed through December 31, 2002. Cancer incidence was ascertained through the nationwide Swedish Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated to compare cancer incidence of women with implants with women in the general population. Mean follow-up among women with breast implants was 18.4 years (range = 0.1-37.8 years). The incidence of breast cancer was below expectation (SIR = 0.7, 95% CI = 0.6 to 1.0), whereas lung cancer was above expectation (SIR = 2.2, 95% CI = 1.3 to 3.4). With respect to cancer overall and all other specific cancer sites, including brain cancer and sarcoma, non-Hodgkin lymphoma, and multiple myeloma, no statistically significantly increased or decreased SIRs were observed. Stratification by duration of follow-up revealed no statistically significantly increased or decreased SIR, with the exception of a two- to threefold excess of lung cancer among women followed for more than 15 years, which would be expected due to the high prevalence of smoking among the Swedish women with implants in our study.

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 nationwide epidemiologic study of breast cancer incidence following breast reduction surgery in a large cohort of Swedish women

While it has been demonstrated that prophylactic mastectomy reduces breast cancer incidence among women at high risk, many women often consider this disfiguring surgery unacceptable. One alternative approach may be breast reduction surgery. In order to evaluate the long-term incidence of breast cancer following surgical removal of breast tissue, we have extended by 9 years the follow-up period of our earlier retrospective cohort study of Swedish women electing cosmetic breast reduction surgery (n=30,444) between 1965 and 1993, yielding an average of nearly 16 years of follow-up. Cancer incidence through 2002 was ascertained via the Swedish Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated comparing women who underwent breast reduction surgery with women in the general Swedish population. Breast cancer was observed in 443 women versus 624 expected for a statistically significant reduced SIR of 0.71 (95% CI=0.65-0.78). Analyses by age at surgery, time since surgery or calendar year of surgery revealed similar reductions in risk. Our study of over 30,000 women with long-term follow-up offers further evidence that women undergoing breast reduction surgery have reduced breast cancer risk. As the evidence from large-scale cohort studies accumulates, direct testing of this reduction in risk through clinical trials should be considered.

Reconstructive Breast Implantation After Mastectomy for Breast Cancer

BACKGROUND

Clinical reports have raised concern about local complications following breast implantation used in reconstructive or cosmetic surgery, but there is a shortage of epidemiological studies in this area.

OBJECTIVE

To assess in a prospective epidemiological manner the occurrence of short-term local complications in a nationwide implantation registry.

DESIGN, SETTING, AND PARTICIPANTS

The Danish Registry for Plastic Surgery of the Breast prospectively collects preoperative, perioperative, and postoperative information on Danish women undergoing breast augmentation. Through the registry, we collected data on short-term local complications among 574 women who underwent postmastectomy reconstruction with breast implants from June 1, 1999, through July 24, 2003.

MAIN OUTCOME MEASURES

Complication incidence rates.

RESULTS

Thirty-one percent of the women who underwent initial implantation developed at least 1 adverse event. Forty-nine percent of the adverse events occurred within 3 months after implantation and 67% within 6 months. Surgical intervention was required after initial implantation among 21% of women, most frequently because of capsular contracture, asymmetry, or displacement of the implant. Thirty-six percent of women who underwent subsequent implantation experienced at least 1 adverse event, and 21% underwent surgical intervention to treat definitive complications or to optimize cosmetic result.

CONCLUSIONS

Women who undergo postmastectomy breast implantation frequently experience short-term local complications. Surgical or medical intervention is commonly required during the reconstructive course, but reconstruction failure (loss of implant) is rare. However, when weighing benefits and risks associated with reconstruction, the patient should consider that breast reconstruction is a process involving planned and unplanned supplementary surgical correction to achieve the desired result.

The Natural History of Chronic Renal Failure: Results From an Unselected, Population-Based, Inception Cohort in Sweden

BACKGROUND

Mortality rates in patients with chronic renal failure (CRF) are high both before and after start of renal replacement therapy (RRT). However, few studies of mortality and progression have been performed in an unselected CRF population.

METHODS

We followed up a population-based inception cohort of 920 men and women aged 18 to 74 years who had CRF (serum creatinine level > 3.4 mg/dL [>300 micromol/L] for men and >2.8 mg/dL [>250 micromol/L] for women) for 55 to 79 months. Relationships between the outcomes (death and start of RRT) and independent variables under study (age, sex, primary renal disease, body mass index [BMI], and glomerular filtration rate [GFR] at entry) were explored by using Cox regression models.

RESULTS

Seven hundred thirty-nine patients (80%) started RRT during the follow-up period. As expected, GFR at entry was clearly linked to the incidence of RRT (P < 0.0001). Age was related inversely to incidence of RRT (adjusted relative risk for patients > or =65 years relative to patients <45 years, 0.72; 95% confidence interval, 0.57 to 0.90). Men progressed to RRT more often than women (adjusted relative risk, 1.59; 95% confidence interval, 1.35 to 1.88). BMI was unrelated to RRT incidence. By the end of follow-up, 389 patients with CRF (42%) had died, 89 of them (10%) before the start of RRT. The most common primary cause of death was cardiovascular disease (37.5%). Characteristics significantly related to a greater mortality rate included older age, diagnoses of diabetic nephropathy and nephrosclerosis, and low BMI.

CONCLUSION

Preuremic characteristics (age, sex, primary renal diagnosis, BMI, and GFR) are predictive of prognosis in unselected patients with CRF.

Cancer risk among Danish women with cosmetic breast implants

The available epidemiologic evidence does not support a carcinogenic effect of silicone breast implants on breast or other cancers. Data on cancer risk other than breast cancer are limited and few studies have assessed cancer risk beyond 10-15 years after breast implantation. We extended follow-up of our earlier cohort study of Danish women with cosmetic breast implants by 7 years, yielding 30 years of follow-up for women with longest implant duration. The study population consisted of women who underwent cosmetic breast implant surgery at private clinics of plastic surgery (n = 1,653) or public hospitals (n = 1,110), and a control group of women who attended private clinics for other plastic surgery (n = 1,736), between 1973-95. Cancer incidence through 2002 was ascertained using the Danish Cancer Registry. Risk evaluation was based on computation of standardized incidence ratios (SIR) and Cox proportional hazards models, adjusting for age, calendar period and reproductive history. We observed 163 cancers among women with breast implants compared to 136.7 expected based on general population rates (SIR = 1.2; 95% confidence interval [CI] = 1.0-1.4), during a mean follow-up period of 14.4 years (range = 0-30 years). Women with breast implants experienced a reduced risk of breast cancer (SIR = 0.7; 95% CI = 0.5-1.0), and an increased risk of non-melanoma skin cancer (SIR = 2.1; 95% CI = 1.5-2.7). Stratification by age at implantation, calendar year at implantation and time since implantation showed no clear trends, however, the statistical precision was limited in these analyses. When excluding non-melanoma skin cancer, the SIR for cancer overall was 1.0 (95% CI = 0.8-1.2). With respect to other site-specific cancers, no significantly increased or decreased SIR were observed. Similar results were found when directly comparing women who had implants at private clinics with women who attended private clinics for other plastic surgery, with rate ratios for cancer overall, breast cancer and non-melanoma skin cancer of 1.1 (95% CI = 0.8-1.6), 0.7 (95% CI = 0.4-1.3) and 1.5 (95% CI = 0.8-2.7), respectively. In conclusion, our study lends further support to the accumulating evidence that silicone breast implants are not carcinogenic. Reasons for the consistently reported deficit of breast cancer among women with breast implants remain unclear, whereas increased exposure to sunlight may explain the excess occurrence of non-melanoma skin cancer. We found no indication of delayed diagnosis of breast cancer due to the presence of breast implants.

The association of body mass index and pancreatic cancer in residents of southeastern Michigan, 1996-1999

Increased body mass index has emerged as a potential risk factor for pancreatic cancer. The authors examined whether the association between body mass index and pancreatic cancer was modified by gender, smoking, and diabetes in residents of southeastern Michigan, 1996-1999. A total of 231 patients with newly diagnosed adenocarcinoma of the exocrine pancreas were compared with 388 general population controls. In-person interviews were conducted to ascertain information on demographic and lifestyle factors. Unconditional logistic regression models estimated the association between body mass index and pancreatic cancer. Males' risk for pancreatic cancer significantly increased with increasing body mass index (p(trend) = 0.048), while no relation was found for women (p(trend) = 0.37). Among nonsmokers, those in the highest category of body mass index were 3.3 times (95% confidence interval: 1.2, 9.2) more likely to have pancreatic cancer compared with those with low body mass index. In contrast, no relation was found for smokers (p(trend) = 0.94). While body mass index was not associated with pancreatic cancer risk among insulin users (p(trend) = 0.11), a significant increase in risk was seen in non-insulin users (p(trend) = 0.039). This well-designed, population-based study offered further evidence that increased body mass index is related to pancreatic cancer risk, especially for men and nonsmokers. In addition, body mass index may play a role in the etiology of pancreatic cancer even in the absence of diabetes.

The Diagnosis of Silicone Breast-Implant Rupture

The objective was to evaluate the usefulness of clinical examination in the evaluation of breast-implant integrity, using the diagnosis at magnetic resonance imaging (MRI) as the "gold standard." Fifty-five women with 109 implants underwent a breast examination either just before or shortly after an MRI examination. Twenty-four of 109 implants were clinically diagnosed with possible rupture or rupture. Eighteen of the 24 implants were ruptured according to the MRI examination (75%). Eighty-five implants were clinically classified as intact, and 43 of these were actually ruptured at MRI (51%). The sensitivity of the clinical examination for diagnosing rupture was thus 30% and the specificity 88%. The positive predictive value of a clinical diagnosis of rupture was 75%, and the negative predictive value was 49%. In this study, we found that when a clinical examination is used as the sole diagnostic tool to identify implant rupture, neither the sensitivity nor the specificity is acceptable.

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.

A Cohort Study of Parkinson???s Disease and Other Neurodegenerative Disorders in Danish Welders

OBJECTIVE

We sought to evaluate rates of hospitalizations for neurodegenerative disorders in a cohort of Danish metal manufacturing employees.

METHODS

A retrospective cohort study was conducted from 1977 to 2002 among 27,839 male Danish metal-manufacturing employees, with 9,817 of those employed in departments engaged in mild or stainless-steel welding and 6,163 welders.

RESULTS

The standardized hospitalization ratio and 95% confidence intervals (CI) for Parkinson's disease were 0.9 (CI = 0.7-1.2) for men in steel-manufacturing companies, 1.0 (CI = 0.7-1.5) for men in welding departments, and 0.9 (CI = 0.4-1.5) for welders. Observed numbers for other neurological conditions were small and not above population expectations. Analyses for time period worked, age, and duration of welding were unremarkable.

CONCLUSIONS

This relatively large cohort study with long-term follow-up provides no support for the hypothesis that rates of hospitalization for Parkinson's disease or other neurological conditions are elevated under the exposure circumstances of these Danish workers.

Cancer risk among statin users: a population-based cohort study

Hydroxymethylglutaryl-CoA reductase inhibitors (statins) have been linked with potential chemopreventive effects; however, the data are conflicting. We conducted a population-based cohort study using data from the Prescription Database of North Jutland County and the Danish Cancer Registry for the period 1989-2002. In a study population of 334,754 county residents, we compared overall and site-specific cancer incidence among 12,251 statin users (> or =2 prescriptions) with cancer incidence among nonusers and users of other lipid-lowering drugs (n = 1,257). Statistical analyses were based on age-standardization and Poisson regression analysis, adjusting for age, gender, calendar period and use of NSAIDs, hormone replacement therapy and cardiovascular drugs. We identified 398 cancer cases among statin users during a mean follow-up period of 3.3 years (range 0-14 years). The age- and gender-standardized incidence rates of cancer overall were 596 per 100,000 person-years among statin users, 645 per 100,000 person-years among nonusers and 795 per 100,000 person-years among users of other lipid-lowering drugs. Adjusted rate ratios for cancer overall among statin users were 0.86 (95% CI, 0.78-0.95) compared to nonusers and 0.73 (95% CI, 0.55-0.98) compared to users of other lipid-lowering drugs. No significantly increased or decreased rate ratios were observed for any of the studied site-specific cancers (liver, colorectum, lung, breast, prostate, female genital organs and lymphatic and haematopoietic tissue), but most estimates tended to be less than 1.0. Stratification by duration of follow-up or number of prescriptions revealed no clear trends. In summary, individuals prescribed statins experienced a slightly reduced cancer incidence compared to population controls of nonusers and users of other lipid-lowering drugs. Larger and longer-term studies are needed to determine the potentially protective effect of statin use on cancer development.

Surgical Intervention and Capsular Contracture After Breast Augmentation

Epidemiologic data on local complications after breast augmentation are scarce. In particular, few prospectively collected data are available on modern breast implants on this issue. Using data from the Danish Registry for Plastic Surgery of the Breast, the authors examined determinants of surgery-requiring complications and capsular contracture grades III to IV among 2277 women who underwent cosmetic breast implantation from June 1999 through April 2003. During an average follow-up period of 1.6 years after implantation, 4.3% of these women (3% of implants) required secondary surgery as a result of short-term complications. The most frequent clinical indications for surgery were displacement of the implant (38%), capsular contracture grades III to IV (16%), ptosis (13%), and hematoma (11%). Overall, the authors found that inframammary incision and subglandular placement were associated with decreased risks of developing complications requiring surgical intervention, whereas implants larger than 350 mL increased the risk of such complications (relative risk [RR], 2.3; 95% confidence interval [CI], 1.3-4.0). Thirty-nine Baker III to IV capsular contractures were identified, of which 22 were treated surgically within the study period. Submuscular placement of the implant decreased the risk of capsular contracture grades III to IV (RR, 0.3; 95% CI, 0.2-0.8), whereas surgical routes other than inframammary and drainage of implant cavity were associated with increased risk of capsular contracture. Current surgical practices and modern implants used for breast augmentation produce fewer short-term complications than procedures and devices of the past. This prospective study indicates that surgical procedures are more important predictors for local (short-term) complications than implant or patient characteristics.

Retrospective Cohort Mortality Study of Workers Engaged in Motion Picture Film Processing

OBJECTIVE

To assess potential health risks associated with work in a large motion picture film-processing facility.

METHODS

A retrospective cohort mortality study was conducted during 1960-2000 among 2646 film workers. Job family categories, created from detailed employee work history information, were used to evaluate chemical exposure patterns.

RESULTS

Overall mortality was as expected (standardized mortality ratio [SMR] = 1.1; 95% confidence interval [CI] = 1.0-1.2). Statistically significant associations were found for suicides (SMR = 2.0; 95% CI = 1.2-3.0) among the hourly workers and AIDS (SMR = 5.3; 95% CI = 1.7-12.3) among the administrative workers. Film developers had increases of respiratory cancer (SMR = 1.9; 95% CI = 1.1-3.0) and suicides (SMR = 2.4; 95% CI = 1.0-4.7), whereas film assemblers had an increase in suicides (SMR = 2.4; 95% CI = 1.2-4.4) only.

CONCLUSIONS

Excess deaths resulting from suicides and AIDS among the workforce suggest that nonoccupational influences may be involved in the mortality of this cohort and warrant further investigations.

Untreated Silicone Breast Implant Rupture

Implant rupture is a well-known complication of breast implant surgery that can pass unnoticed by both patient and physician. To date, no prospective study has addressed the possible health implications of silicone breast implant rupture. The aim of the present study was to evaluate whether untreated ruptures are associated with changes over time in magnetic resonance imaging findings, serologic markers, or self-reported breast symptoms. A baseline magnetic resonance imaging examination was performed in 1999 on 271 women who were randomly chosen from a larger cohort of women having cosmetic breast implants for a median period of 12 years (range, 3 to 25 years). A follow-up magnetic resonance imaging examination was carried out in 2001, excluding women who underwent explantation in the period between the two magnetic resonance imaging examinations (n = 44). On the basis of these examinations, the authors identified 64 women who had at least one ruptured implant at the first magnetic resonance imaging examination and, for comparison, all women who had intact implants at both examinations (n = 98). Magnetic resonance images from the two examinations were compared and changes in rupture configuration were evaluated. Comparisons were also made for self-reported breast symptoms occurring during the study period and for changes in serum values of antinuclear antibodies, rheumatoid factor, and cardiolipin antibodies immunoglobulin G and immunoglobulin M. The majority of the women with implant rupture had no visible magnetic resonance imaging changes of their ruptured implants. For 11 implants (11 percent) in 10 women, the authors observed progression of silicone seepage, either as a conversion from intracapsular into extracapsular rupture (n = 7), as progression of extra-capsular silicone (n = 3), or as increasing herniation of the silicone within the fibrous capsule (n = 1); however, in most cases, these changes were minor. Some changes could be ascribed to trauma, but others seemed spontaneous. There was no increase in levels of autoantibodies during the study period in either study group. Women with untreated implant ruptures reported a significant increase in nonspecific breast changes (odds ratio, 2.1; 95 percent confidence interval, 1.2 to 3.8) compared with women without ruptures. On the basis of this first study of women with untreated silicone breast implant rupture, the authors conclude that implant rupture is a relatively harmless condition, which only rarely progresses and gives rise to notable symptoms. Even so, because of a small risk of silicone spread, the authors suggest that women with implant ruptures be followed clinically, if not operated on. Because implant ruptures often occur asymptomatically, any woman with silicone implants, regardless of rupture status, should be evaluated at regular intervals.

Long-Term Health Status of Danish Women with Silicone Breast Implants

Long-term safety data are important in the evaluation of possible adverse health outcomes related to silicone breast implants. The authors evaluated long-term symptoms and conditions and medication use among 190 Danish women with cosmetic silicone breast implants compared with 186 women who had undergone breast reduction surgery and with 149 women from the general population. Breast implant and reduction surgeries were performed from 1973 to 1988 at one public hospital and one private plastic surgery clinic. Among women with breast implants, the average implantation time was 19 years, 60 percent (n = 114) had only one implantation, and 10 percent (n = 19) had undergone explantation before the time of study (1997 to 1998). The authors found no material differences in self-reported diseases or symptoms among study groups, except for breast pain, which was reported nearly three times as often by women with implants than by women with breast reduction (odds ratio, 2.8; 95 percent confidence interval, 1.4 to 5.3). Approximately 80 percent of women in each study group reported at least one symptom. No consistent differences were observed in the seroprevalences of antinuclear antibodies or other autoantibodies. Self-reported use of psychotropic drugs was higher among women with breast implants than among either control group. The authors conclude that long-term cosmetic breast implantation may cause capsular contracture and breast pain but does not appear to be associated with other symptoms, diseases, or autoimmune reactivity. The authors' finding of excess use of drugs for treatment of depression and anxiety among women with breast implants may warrant further investigation.

Absence of association between organic solvent exposure and risk of chronic renal failure: a nationwide population-based case-control study

Exposure to organic solvents has been suggested to cause or exacerbate renal disease, but methodologic concerns regarding previous studies preclude firm conclusions. We examined the role of organic solvents in a population-based case-control study of early-stage chronic renal failure (CRF). All native Swedish residents aged 18 to 74 yr, living in Sweden between May 1996 and May 1998, formed the source population. Incident cases of CRF in a pre-uremic stage (n = 926) and control subjects (n = 998), randomly selected from the study base, underwent personal interviews that included a detailed occupational history. Expert rating by a certified occupational hygienist was used to assess organic solvent exposure intensity and duration. Relative risks were estimated by odds ratios (OR) in logistic regression models, with adjustment for potentially important covariates. The overall risk for CRF among subjects ever exposed to organic solvents was virtually identical to that among never-exposed (OR, 1.01; 95% confidence interval [CI], 0.81 to 1.25). No dose-response relationships were observed for lifetime cumulative solvent exposure, average dose, or exposure frequency or duration. The absence of association pertained to all subgroups of CRF: glomerulonephritis (OR, 0.96; 95% CI, 0.68 to 1.34), diabetic nephropathy (OR, 1.02; 95% CI, 0.74 to 1.41), renal vascular disease (OR, 1.16; 95% CI, 0.76 to 1.75), and other renal CRF (OR, 0.92; 95% CI, 0.66 to 1.27). The results from a nationwide, population-based study do not support the hypothesis of an adverse effect of organic solvents on CRF development, in general. Detrimental effects from subclasses of solvents or on specific renal diseases cannot be ruled out.

Self-reported Musculoskeletal Symptoms Among Danish Women With Cosmetic Breast Implants

BACKGROUND

No epidemiological evidence of an association between silicone breast implants and connective tissue disease has been found. Based on case reports, it has been hypothesized that silicone breast implants may be associated with a unique rheumatic symptom cluster termed "atypical connective tissue disease."

MATERIAL AND METHODS

We have evaluated self-reported rheumatic symptoms among women who received breast implants between 1977 and 1997 at 2 private plastic surgery clinics in Denmark. Women with other cosmetic surgery, including breast reduction, as well as women from the general population, were identified as controls.

RESULTS

No statistically significant differences in mild (odds ratio [OR] = 0.9; 95% confidence interval [CI] = 0.6-1.3), moderate (OR = 0.7; 95% CI = 0.4-1.2), or severe (OR = 1.1; 95% CI = 0.6-2.1) musculoskeletal symptoms were observed when women with breast implants were compared with women with other cosmetic surgery. Compared with women from the general population, women with breast implants were statistically significantly less likely to have mild or moderate musculoskeletal symptoms (OR = 0.5; 95% CI = 0.3-0.7 and OR = 0.3; 95% CI = 0.2-0.5, respectively); for severe symptoms the deficit was not statistically significant (OR = 0.7; 95% CI = 0.3-1.3). For individual symptom groups, there was no consistent pattern of reporting among women with implants.

CONCLUSION

We did not find an excess of rheumatic symptoms or symptom clusters among women with breast implants. In fact, the occurrence of mild, moderate, and severe musculoskeletal symptoms was generally lower among women with implants compared with women with other cosmetic surgery and women in the general population.

Incidence and Severity of Short-Term Complications After Breast Augmentation

The frequency and severity of local complications remain the primary safety issues with silicone breast implants. The Danish Registry for Plastic Surgery of the Breast (DPB), established in 1999, prospectively collects pre-, peri- and postoperative information regarding Danish women undergoing breast augmentation. Through DPB, we conducted a prospective follow-up study of short-term local complications among 1090 women who underwent cosmetic breast implantation from June 1999 through October 2002. Nineteen percent of women who underwent initial implantation developed at least 1 adverse effect. Forty percent of the adverse effects occurred within 3 months of implantation; 79%, within 6 months. Capsular contracture grade II-IV was observed among 4.1% of women in the 2-year follow-up period. Overall, 97 (29%) of the 344 adverse effects among 55 (6%) of the 971 women required surgical intervention. A higher incidence of adverse effects typically occurred after subsequent implantations. According to the DPB experience, we conclude that most short-term postoperative adverse effects following cosmetic implantation are clinically insignificant and do not require treatment and that short-term complications requiring adjuvant treatment are rare.

Incidence of silicone breast implant rupture

HYPOTHESIS

The incidence of silicone breast implant rupture varies with implantation time and type of implant.

OBJECTIVE

To measure the incidence of implant rupture by repeated magnetic resonance imaging (MRI) among women with silicone breast implants.

DESIGN, SETTING, AND PARTICIPANTS

In 1999, 271 women who had received breast implants at least 3 years before, and who were randomly chosen from a larger cohort of women with cosmetic breast implants, underwent a baseline MRI. A second MRI was performed in 2001; 317 silicone implants (in 186 women) that were intact at the baseline MRI (n = 280) or were intact at baseline but removed before the second MRI (n = 37) were included in the rupture incidence analyses.

MAIN OUTCOME MEASURES

Implants were diagnosed with definite or possible rupture. Crude and implant age-adjusted incidence rates were calculated, and implant survival was estimated based on the observed rupture rates.

RESULTS

We found 33 definite ruptures (10%) and 23 possible ruptures (7%) during the 2-year period. The overall rupture incidence rate for definite ruptures was 5.3 ruptures/100 implants per year (95% confidence interval, 4.0-7.0). The rupture rate increased significantly with increasing implant age. Double-lumen implants were associated with substantially lower rupture risk than single-lumen implants. For modern implants intact 3 years after implantation, we estimated rupture-free survival of 98% at 5 years and 83% to 85% at 10 years.

CONCLUSIONS

The risk of implant rupture increases with implant age. A minimum of 15% of modern implants can be expected to rupture between the third and tenth year after implantation.

The Danish Registry for Plastic Surgery of the Breast: establishment of a nationwide registry for prospective follow-up, quality assessment, and investigation of breast surgery

Although numerous epidemiologic studies have examined the long-term safety of silicone breast implants during the past decade, there is a relative lack of surveillance data on short-term health effects and complications following cosmetic surgery of the breast. The Danish Registry for Plastic Surgery of the Breast, established in May of 1999, provides plastic surgeons with a nationwide system for the collection of preoperative, perioperative, and postoperative data on women undergoing breast implantation, breast reduction, or mastopexy. The purpose of the Registry is to examine short-term and, eventually, long-term local complications and possible health effects, and to contribute to an ongoing evaluation of surgical results and surveillance of the products. Furthermore, the Registry will allow the identification of new areas for research into cosmetic and reconstructive breast surgery. Women accepting registration in the Danish Registry for Plastic Surgery of the Breast complete a self-administered questionnaire focusing on medical history and demographic and behavioral factors. Preoperative blood samples are drawn for storage. Surgical data, postoperative results, and complications are registered following surgery and at postoperative visits. Currently, registration has been initiated at 24 private and public clinics, representing more than 80 percent of the plastic surgery clinics in Denmark. As of November of 2001, a total of 1472 women with breast implants and 560 women with breast reduction were included in the Registry. These figures are expected to increase annually by 1000 women undergoing breast implantation and 500 women undergoing breast reduction or mastopexy. The authors present their experience of establishing the first nationwide comprehensive clinical-epidemiologic database and biological bank for cosmetic and reconstructive surgery procedures.

A nationwide followup study of autoimmune and connective tissue disease among hip and knee implant patients

Because implants can provoke varied immune system responses, we assessed whether hip and knee implant recipients had an increased risk of autoimmune/connective tissue diseases (AI/CTDs). Using national registry data from Sweden, we compared hospitalization rates for AI/CTD in 101,771 hip and 23,891 knee implant recipients to rates in the general population. Hip patients were followed up to 22 years and knee patients up to 14 years postimplantation. Our findings indicate that it is unlikely that hip or knee implantation results in any increased risk for most AI/CTDs. After long-term followup, the associations we observed with polyarteritis nodosa and fibrositis could be the basis for future investigations.

A cohort mortality study among titanium dioxide manufacturing workers in the United States

Although titanium dioxide (TiO2) is generally regarded as a nontoxic mild pulmonary irritant, some laboratory studies have reported lung adenomas in rats exposed to high levels of TiO2. Limited data on health effects among humans exist. A retrospective cohort mortality study was conducted among 4241 TiO2 workers who were employed for at least 6 months, on or after January 1, 1960, at four TiO2 plants in the United States. Exposure categories, defined by plant, job title, and calendar years in the job, were created to examine mortality patterns in those jobs where the potential for TiO2 exposure is greatest. Standardized mortality ratios (SMRs) and their 95% confidence intervals (CI) were calculated to compare the mortality pattern of the workers with the general background population. Relative risks were estimated and trend tests were conducted to examine risk of disease among different exposure level groups in internal analyses. Workers experienced a significantly low overall mortality (SMR = 0.8; 95% CI = 0.8-0.9). No significantly increased SMRs were found for any specific cause of death. Deaths from lung cancer were as expected, and SMRs for this cancer did not increase with increasing TiO2 levels. Workers in jobs with greatest TiO2 exposure had significantly fewer than expected total deaths (SMR = 0.7; 95% CI = 0.6-0.9). Internal analyses revealed no significant trends or exposure-risk associations for total cancers, lung cancer, or other causes of death. Results from our study indicate that the exposures at these United States plants are not associated with increases in the risk of death from cancer or other diseases. Moreover, workers with likely higher levels of TiO2 exposure had similar mortality patterns to those with less exposure, as internal analyses among workers revealed no increase in mortality by level of TiO2 exposure.

Self-reported diseases and symptoms by rupture status among unselected Danish women with cosmetic silicone breast implants

Epidemiologic evidence does not support an association between silicone breast implants and connective tissue or other rheumatic diseases. However, a recent study has suggested that women with ruptured implants may be at increased risk of developing fibromyalgia. An analysis of adverse health outcomes according to breast implant rupture status was conducted in 238 unselected Danish women with cosmetic silicone breast implants. Ninety-two of the women had definite implant rupture, and 146 had intact implants as determined by magnetic resonance imaging. Before undergoing imaging, the women provided blood samples and completed a self-administered questionnaire. Women with ruptured implants overall, and the subgroup with extracapsular ruptures (n = 23), were compared with women with intact implants regarding a number of self-reported diseases and symptoms and the presence of specific autoantibodies, such as antinuclear antibodies, rheumatoid factor, and cardiolipin immunoglobulin G and M antibodies. Overall, there were no differences in the occurrence of self-reported diseases or symptoms or in the presence of autoantibodies between women with intact implants and women with ruptured implants, including extracapsular rupture. The only exception was capsular contracture, which was reported six times more frequently by women with extracapsular ruptures than by women with intact implants (OR, 6.3; 95 percent CI, 1.7 to 23.5). In conclusion, this study of unselected women with silicone breast implants could establish no association between silicone implant rupture and specific diseases or symptoms related to connective tissue disease or other rheumatic conditions, except for an excess of capsular contracture among women with extracapsular rupture.

Characteristics of women with cosmetic breast implants compared with women with other types of cosmetic surgery and population-based controls in Denmark

Herein the authors describe characteristics of women with breast implants compared with women with other types of cosmetic surgery as well as population controls. All women who acquired breast implants from 1977 to 1997 were identified from the files of two private plastic surgery clinics in Denmark. Patient characteristics were obtained through a self-administered questionnaire. The magnitude of differences between patient and control groups was estimated using odds ratios and 95% confidence intervals. Women with breast implants had a significantly lower body mass index and reported a two-fold greater incidence of current smoking compared with women from the general population and compared with women with other cosmetic surgery. Women with implants reported a greater number of full-term pregnancies and were less likely than controls to have had their first birth at age 30 years or older. Women with implants were not more likely than women in either control group to report a history of diseases, including connective tissue diseases, cancer, or depression before their implant surgery. Women with cosmetic breast implants differ from women with other forms of cosmetic surgery and from general population controls with respect to characteristics that may importantly influence health outcomes and that need to be addressed in future breast implant studies.

Socio-economic status and chronic renal failure: a population-based case-control study in Sweden

BACKGROUND

Low socio-economic status is associated with the occurrence of several different chronic diseases, but evidence regarding renal disease is scant. To explore whether the risk of chronic renal failure varies by socio-economic status, we performed a population-based case-control study in Sweden.

METHODS

All native residents from May 1996 to May 1998, aged 18-74 years, formed the source population. Cases (n = 926) were incident patients with chronic renal failure in a pre-uraemic stage. Control subjects (n = 998) were randomly selected within the source population. Exposures were assessed at personal interviews and relative risks were estimated by odds ratios (OR) in logistic regression models, with adjustment for age, sex, body mass index (BMI), smoking, alcohol consumption and regular analgesics use.

RESULTS

In families with unskilled workers only, the risk of chronic renal failure was increased by 110% [OR = 2.1; 95% confidence interval (CI), 1.1-4.0] and 60% (OR = 1.6; 95% CI, 1.0-2.6) among women and men, respectively, relative to subjects living in families in which at least one member was a professional. Subjects with 9 years or less of schooling had a 30% (OR = 1.3; 95% CI, 1.0-1.7) higher risk compared with those with a university education. The excess risk was of similar magnitude regardless of underlying renal disease.

CONCLUSIONS

Low socio-economic status is associated with an increased risk of chronic renal failure. The moderate excess was not explained by age, sex, BMI, smoking, alcohol or analgesic intake. Thus, socio-economic status appears to be an independent risk indicator for chronic renal failure in Sweden.

Incidence of cancer among patients with knee implants in Sweden, 1980-1994

BACKGROUND

As knee implants become more common, it is important to study their potential health risks. We investigated cancer occurrence in a nationwide population-based cohort of 30,011 patients who underwent knee replacement surgery in Sweden from 1980 to 1994.

METHODS

Patients were followed from 1 year after the date of their surgery through December 31, 1995, accruing 122,616 person-years of observation. The average follow-up time was 4.3 years, with 2365 patients followed for 10 years or more.

RESULTS

Overall cancer incidence was not elevated compared with the general population of Sweden (standardized incidence ratio [SIR] = 1.03; 95% confidence interval [CI] = 0.98-1.08). A reduced rate for all respiratory cancers (SIR = 0.73; 95% CI = 0.59-0.91) and for lung cancer (SIR = 0.73; 95% CI = 0.58-0.91) was found among both men and women. Elevated rates were found for prostate (SIR = 1.20; 95% CI = 1.06-1.34) and bone cancer (SIR = 6.00; 95% CI = 1.24-17.52) in men. The bone cancer excess was based on three observed cases, two of which occurred at a site unrelated to the implant and the site of the third tumor is unknown. Rates of connective tissue cancer and leukemia-lymphoma were not elevated significantly among knee implant recipients. Long-term follow-up (>or= 10 years) did not show a significant excess risk for all cancer (SIR = 1.10; 95% CI = 0.86-1.38) or for any site-specific cancer, including bone cancer, lymphoma, or leukemia. Subgroup analyses for patients with rheumatoid arthritis produced results similar to the overall results.

CONCLUSIONS

This epidemiologic study of cancer risk among patients with knee implants is the largest to date. It provides evidence that the incidence of cancer among patients with knee implants is similar to that of the general population. Continued follow-up of this cohort is warranted to evaluate further potential long-term effects of these implants.

The reliability of dietary data for self- and next-of-kin respondents

BACKGROUND

In case-control studies, recalled dietary data from next-of-kin are sometimes used as a surrogate measure of exposure; however, there is limited evidence comparing the ability of study participants and next-of-kin surrogates for the reliability of their responses with respect to past dietary recall.

METHODS

We compared dietary information from 303 subjects who were administered a food frequency questionnaire in 1980 with that from 196 of the same subjects and 107 next-of-kin of deceased subjects 5 years later, but with reference to 1980 diet. Agreement between 1980 and 1985 reporting with respect to food groups, food preparation methods, and adherence to special diets was primarily assessed using the kappa statistic.

RESULTS

The concordance between 1980 and 1985 reporting of specific food groups was generally poor. Regarding various methods of cooking meats and the use of different types of cooking fats, next-of-kin respondents showed very poor agreement with the reporting of their deceased relatives, and within-subject agreement was also poor for frying meats, baking meats, and for cooking with margarine and vegetable oil. Subjects and next-of-kin were able to reproduce earlier reporting of a special ulcer diet, but not diabetic or low-salt diets. Overall, subjects tended to have better agreement with their own earlier reporting than did next-of-kin, and spouses were found to be more reliable next-of-kin respondents than other relatives.

CONCLUSIONS

Dietary data collected retrospectively from next-of-kin may be unreliable.

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.