Biomedical subjects

L Lipworth

Publications and source records attributed to L Lipworth.

At least 37 records · Page 2Linked to original sources

PubMed2000

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.

Adult↗

PubMed2000

Epidemiologic aspects of renal cell cancer.

Renal cell cancer accounts for about 2% of cancers worldwide. It has been increasing in incidence in North America and northern Europe, but not in other areas of the world. In the United States the rate of increase has been about 3% per year, with the highest rates now seen among blacks. Survival has improved, with the 5-year relative survival rate increasing from 30% to 40% in the 1960s to between 50% and 60% in the 1990s. A large number of epidemiologic studies, particularly case-control investigations, have searched for clues to the etiology. Cigarette smoking is a causal factor in the development of renal cell cancer. Virtually every study has identified obesity or high relative weight as another major determinant, particularly among women. High blood pressure or its medications may also play a role, although the mechanism is unknown. Occupational exposures such as asbestos, coke oven emissions, gasoline, and solvents have been related to an excess risk, but no convincing evidence exists regarding these or any other occupational factor. An inverse association between risk and intake of fruits and vegetables has been seen in a number of studies and remains one of the few consistent dietary findings. A relation with coffee, alcohol, or any other beverage has not been demonstrated for renal cell cancer and is unlikely to exist. Genetic susceptibility plays a significant role in an unknown portion of cases, likely through a number of mechanisms. Future etiologic studies should focus on the mechanism by which obesity increases risk, the role of high blood pressure and its medications, and the reasons for the remarkedly rapid increase in incidence among blacks in the United States.

Carcinoma, Renal Cell↗

PubMed1999

Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk: a nested case-control study.

An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.

Adult↗

PubMed1999

Hip and knee implantations among patients with osteoarthritis and risk of cancer: a record-linkage study from Denmark.

A nationwide cohort study of hip and knee replacement patients in Denmark was undertaken to assess any carcinogenic potential of these implants. A cohort of 22,997 osteoarthritis patients who received hip replacements and of 4,771 osteoarthritis patients who received knee replacements during the period 1977 through 1989 were identified using the nationwide Danish Hospital Discharge Registry. These patients were followed for cancer occurrence through 1993, using the Danish Cancer Registry. There was no overall excess of cancer in either the hip implant cohort [standardized incidence ratio (SIR) = 0.94; 95% confidence interval (CI)= 0.91-0.98] or the knee implant cohort (SIR = 0.97; 95% CI = 0.89-1.06). The risk reduction in both groups of patients reflected for the most part reduced risks for cancers of the respiratory system and the digestive tract, particularly stomach cancer (SIR = 0.69; 95% CI = 0.50-0.81 for hip replacement patients; SIR = 0.46; 95% CI = 0.20-0.91 for knee replacement patients). Elevated risks were observed for melanoma of the skin in both groups of patients. There was no clear excess risk for lymphohematopoietic cancers or malignant neoplasms of the bone or connective tissue among implant patients in either implant group. Contrary to an earlier study in Sweden, we did not find an excess risk for kidney or prostate cancers. In summary, these nationwide results indicate no overall cancer hazard among hip and knee implant patients, but limited follow-up warrants continued surveillance of individuals undergoing these increasingly common surgical procedures.

Aged↗

PubMed1999

Maternal pregnancy hormone levels in an area with a high incidence (Boston, USA) and in an area with a low incidence (Shanghai, China) of breast cancer.

Characteristics probably associated with the fetal hormonal milieu have recently been shown to increase (birth size indicators, prematurity, neonatal jaundice) or decrease (pregnancy toxaemia) breast cancer risk in the female offspring. However, it is unknown whether differences in pregnancy hormone levels may contribute to the marked geographical variation in breast cancer incidence. We have compared, in a highly standardized manner, pregnancy hormone levels in a population with high incidence and one with low incidence of breast cancer. Three hundred and four pregnant Caucasian women in Boston and 334 pregnant Chinese women in Shanghai were enrolled from March 1994 to October 1995. Levels of oestradiol, oestriol, prolactin, progesterone, human growth hormone, albumin and sex hormone-binding globulin were measured in maternal blood at weeks 16 and 27 of gestation and compared between the two study sites using non-parametric Wilcoxon's rank-sum test. Demographical, anthropometrical and pregnancy characteristics were ascertained through interview, and relevant variables concerning delivery and the newborn were abstracted from medical records and paediatric charts. During the first visit, median serum levels of all studied hormones were statistically significant, and in most instances substantially, higher among Chinese women, who have a low incidence of breast cancer, compared with American women, who have a high incidence of breast cancer. An analogous pattern was evident during the second visit, although the relative differences tended to be smaller. Further research is needed to identify lifestyle or other exogenous determinants of pregnancy hormone levels, as well as possible mechanisms by which they may influence carcinogenic processes in the breast and possibly other organs.

Adult↗

PubMed1999

Risk factor patterns for cryptorchidism and hypospadias.

To evaluate the hypothesis of a common etiology for cryptorchidism and hypospadias, we conducted two case-control studies nested in a nationwide cohort in Sweden, using record linkage between the Inpatient and Birth Registries. Cases were 2,782 and 1,220 boys operated for cryptorchidism or hypospadias, respectively. Five matched controls per case were randomly selected. Pregnancy and perinatal data were prospectively recorded in the Birth Registry. Data were modeled through conditional logistic regression. Both cryptorchidism (odds ratio (OR) = 2.22) and hypospadias (OR = 2.75) were positively associated with other congenital malformations and inversely with maternal parity (OR = 0.77 and 0.52, respectively, for parity 4+ compared with primiparae). There is evidence that being born small-for-gestational-age and before the 33rd gestational week have a greater-than-additive effect with respect to both cryptorchidism (OR = 6.19 vs 1.72 expected) and hypospadias (OR = 4.39 vs 2.60 expected) compared with non-small-for-gestational-age boys born at term. Hypospadias was positively associated with severe preeclampsia (OR = 2.11). We conclude that the etiologies of the two conditions are partly shared.

Case-Control Studies↗

PubMed1999

A critical review of the epidemiologic literature on health effects of occupational exposure to vinyl chloride.

We have attempted to critically review and summarise the collective epidemiologic evidence concerning the association of occupational vinyl-chloride exposure with human health outcomes, including cancer, liver cirrhosis, cardiovascular disease, nonmalignant respiratory disease and acroosteolysis. Based on data from individual reports, qualitative and, where possible, quantitative summaries are presented. With respect to cancer, which has been extensively studied, angiosarcoma of the liver is the only malignancy causally related to vinyl-chloride exposure. Hypothesised associations between vinyl chloride and cancers of other sites, namely lung, brain and lymphohaematopoietic system, are not consistently supported by the available data. Similarly, the epidemiologic data relating vinyl chloride to nonmalignant disease, while quantitatively limited and qualitatively suboptimal, do not support a causal association for any of the studied disorders. In summary, a comprehensive review of the relevant epidemiologic literature revealed that occupational vinyl-chloride exposure has not been conclusively or causally linked to any adverse health outcome, with the exception of angiosarcoma of the liver.

Carcinogens↗

PubMed1998

Comparison of risk factors for preeclampsia and gestational hypertension in a population-based cohort study.

The objective of this study was to evaluate and compare risk factor patterns in association with preeclampsia and gestational hypertension. The data were collected from The Swedish Medical Birth Register and include all nulliparas aged 34 years or less who gave birth at the University Hospital of Uppsala, Sweden, during 1987-1993. Of these 10,666 women, 4.4% developed gestational hypertension, and 5.2% developed preeclampsia. The following risk factors were significantly associated with increased risk of preeclampsia: type 1 diabetes (odds ratio = 5.58, 95% confidence interval 2.72-11.43), gestational diabetes (odds ratio = 3.11, 95% confidence interval 1.61-6.00), and twin birth (odds ratio = 4.17, 95% confidence interval 2.30-7.55). The positive associations between these variables and the risk of gestational hypertension were weaker and nonsignificant. Compared with underweight women (body mass index < 19.8), obese women (body mass index > 29) had increased risks of both gestational hypertension (odds ratio = 4.85, 95% confidence interval 1.97-11.92) and preeclampsia (odds ratio = 5.19, 95% confidence interval 2.35-11.48). Significantly lower risks of preeclampsia and gestational hypertension were observed for women born outside Nordic countries and in association with maternal smoking and summer birth. The similarities in risk factor patterns may indicate similarities in the biologic mechanisms underlying the two conditions.

Adult↗

PubMed1998

Prepregnancy weight and the risk of adverse pregnancy outcomes.

BACKGROUND: Obesity before pregnancy is associated with an increased risk of several adverse outcomes of pregnancy. The risk profiles among lean, normal, or mildly overweight women are not, however, well established. METHODS: We studied the associations between prepregnancy body-mass index (defined as the weight in kilograms divided by the square of the height in meters) and the frequency of late fetal death, early neonatal death, preterm delivery, and delivery of a small-for-gestational-age infant in a population-based cohort of 167,750 women in Sweden in 1992 and 1993. The women were categorized as follows, according to body-mass index: lean, less than 20.0; normal, 20.0 through 24.9; overweight, 25.0 through 29.9; and obese, 30.0 or more. The estimates were adjusted for maternal age, parity, smoking, education, whether the mother was living with the father, and maternal height. RESULTS: Among nulliparous women, the odds ratios for late fetal death were increased among women with higher body-mass-index values as compared with lean women, as follows: normal women, 2.2 (95 percent confidence interval, 1.2 to 4.1); overweight women, 3.2 (95 percent confidence interval, 1.6 to 6.2); and obese women, 4.3 (95 percent confidence interval, 2.0 to 9.3). Among parous women, only obese women had a significant increase in the risk of late fetal death (odds ratio, 2.0; 95 percent confidence interval, 1.2 to 3.3). Among nulliparous women, the risk of very preterm delivery (at < or =32 weeks' gestation) was significantly increased among obese as compared with lean women (odds ratio, 1.6; 95 percent confidence interval, 1.1 to 2.3), whereas among parous women, the risk was highest among those who were lean. The risk of delivering a small-for-gestational-age infant decreased more with increasing body-mass index among parous than among nulliparous women. CONCLUSIONS: Higher maternal weight before pregnancy increases the risk of late fetal death, although it protects against the delivery of a small-for-gestational-age infant.

Adolescent↗

PubMed1998

Predictors of sex hormone levels among the elderly: a study in Greece.

This study examines the relationship between a series of epidemiologic parameters (age, height, body mass index (BMI), smoking, alcohol consumption, and coffee drinking) and serum concentrations of testosterone, estradiol, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS). Among 52 healthy, elderly Greek men, we observed that serum levels of DHEAS decreased with increasing age [19% decline per 5-year increase in age, 95% CI, -2.1-(-33.5)], obesity [48% decline for BMI >30 kg/m2 compared to <27 kg/m2, CI, -15.7-(-68.7)], and current smoking [37% decline compared to nonsmokers, CI, -9.5-(-57.2)]. Estradiol concentrations increased with increasing BMI [77.1% increase for BMI >30 kg/m2 compared to <27 kg/m2, CI, -12.0-256.3], alcohol drinking [66% increase for > or = 7 glasses/week compared to <7 glasses/week, CI, 4.4-164.4], and coffee drinking [59% increase for > or = 14 cups/week compared to > or = 14 cups/ week, CI, -0.5-155.9], and decreased among current smokers [40% decline compared to nonsmokers, CI, -64.9-0.8]. SHBG was marginally positively associated with increasing age [13% increase per 5 years, CI, -0.5-29.6]. Testosterone was significantly related only to current smoking [27% decline compared to nonsmokers, CI, -45.4-(-3.1)]. These findings suggest that several variables appear to be associated with sex steroid levels and the influence of these findings on the occurrence of hormone-related conditions warrants further exploration.

Age Factors↗

PubMed1998

Analgesic use and chronic renal failure: a critical review of the epidemiologic literature.

Heavy use of analgesics, particularly over-the-counter (OTC) products, has long been associated with chronic renal failure. Most of the earlier reports implicated phenacetin-containing analgesics as the risk factor. Since the early 1980s. several case-control studies have reported associations between chronic renal failure and use of other forms of analgesics, including acetaminophen, aspirin, and other non-steroidal antiinflammatory drugs (NSAIDs). Findings from these studies, however. should be interpreted with caution because of a number of inherent limitations and potential biases in the study design and data collection procedures. These limitations include: failure to identify patients early enough in the natural history of their disease to collect reliable information on analgesic use at an etiologically relevant time period; selection bias due to incomplete identification of subjects or low response rates; selection of cases and controls from different population bases; failure to employ survey techniques to improve reliability of recall of analgesic use; failure to collect detailed information on analgesic use such as year started and ended and reasons for switching analgesics; lack of standardization in the definition of regular analgesic use; and failure to adjust for phenacetin use and other confounding factors when assessing associations with analgesics other than those containing phenacetin. It is our hope that this review of study design limitations will lead to improvements in future studies of chronic renal failure risk. Since use of analgesics is widespread and new OTC products are introduced frequently, the potential impact of these drugs on the development of chronic renal failure may be significant, thus warranting continued evaluation of these products for any renal toxicity.

Analgesics↗

PubMed1997

Changing seasonality of mortality from coronary heart disease.

CONTEXT: Coronary heart disease is the major cause of mortality in the United States. Factors associated with coronary risk are important to identify. Coronary mortality is greater during the winter months. OBJECTIVE: To investigate whether declining coronary mortality has been accompanied by a change in the seasonal pattern and to investigate the hypothesis that diminishing exposures to environmental cold and heat have affected the seasonal pattern. DESIGN: We used published data on coronary mortality by year to evaluate the time trend in the seasonal pattern. We fit a sine curve to the monthly frequency of deaths in each year and examined the trend over time in the ratio of the peak to the trough of the curve. SETTING: We used monthly coronary deaths in the United States from 1937 through 1991. Deaths by cause and month were not available by geographic area within the United States, but we were able to examine total monthly deaths in 2 regions with contrasting climates, New England and the South. OUTCOME MEASURES: We used the yearly peak-to-trough ratio as our primary outcome and assessed its trend over time by linear regression. We also depicted the time trends using polynomial smoothing. RESULTS: The peak-to-trough ratio diminished by about 2% per year until around 1970, when the trend reversed. In New England, the decline was steeper than in the South, as measured from all deaths. CONCLUSION: Seasonal patterns in coronary mortality in the United States have changed with time. These changes are compatible with the gradual expansion of adequate heating and the subsequent increased use of air-conditioning. Microclimatic influences on coronary mortality could explain in part the socioeconomic gradient of cardiovascular mortality.

Cold Temperature↗

PubMed1997

Intrauterine environment and breast cancer risk in women: a population-based study.

BACKGROUND: The established risk factors for female breast cancer, including nulliparity, age at first birth, age at menarche, and age at menopause, do not adequately explain the occurrence pattern of this cancer. Therefore, additional factors need to be considered to advance our understanding of the causes of breast cancer. Evidence obtained from animals and humans indicates that the perinatal period may be particularly important. Our earlier studies, based on a subsample of the present investigation, suggested that factors thought to be positively associated with estrogen levels during pregnancy are positively associated with breast cancer risk. However, the associated confidence intervals (CIs) were generally wide, indicating considerable variability in the data. PURPOSE: We studied a large number of incident breast cancer case patients and evaluated several perinatal variables in relation to breast cancer risk. These variables included some not previously studied, such as gestational age and neonatal jaundice. We also investigated twin membership as a predictor variable and death from breast cancer, in addition to occurrence of breast cancer, as an alternative outcome variable. METHODS: Birth records for all deliveries at five different hospitals in Sweden during the period from 1874 through 1961 were used to define a large cohort of women. Incident case patients with breast cancer in this cohort were ascertained through the National Cancer Registry or the Uppsala Regional Cancer Registry from 1958 through 1994. In a case-control study nested in the cohort, we abstracted data from birth records on 1068 women with incident breast cancer and on 2727 control subjects individually matched to the case patients on date of birth. We modeled the data through conditional logistic regression. All P values were derived from two-sided statistical tests. RESULTS: We found a markedly reduced risk for breast cancer in women whose mothers had pregnancy toxemia (odds ratio [OR] = 0.41; 95% CI = 0.22-0.79) and an excess risk on women who had neonatal jaundice (OR = 2.16; 95% CI = 1.27-3.67) or who were born before 33 weeks of gestation (OR = 3.96; 95% CI = 1.45-10.81). Compared with the risk for breast cancer in the singleton, the risk for breast cancer in dizygotic twins was increased, although this increase was not statistically significant (OR = 1.72; 95% CI = 0.92-3.20). There was no evidence in these data for a statistically significant or substantial association of breast cancer risk with birth size indicators (i.e., weight and length at birth and placental weight). CONCLUSION AND IMPLICATIONS: Because pregnancy toxemia is associated with low levels of estrogens and neonatal jaundice, severe prematurity, and dizygotic twins with high levels of estrogens, our findings suggest that estrogens and other hormonal factors, known to influence breast cancer risk in the adult, may also play a critical role during the intrauterine period.

Breast Neoplasms↗

PubMed1997

Serum steroids in relation to prostate cancer risk in a case-control study (Greece).

Blood samples were collected from 52 incident cases of histologically confirmed prostate cancer and 52 age- and town of residence-matched healthy controls in Athens, Greece. Samples were analyzed blindly in Boston, Massachusetts (USA) for testosterone (T), estradiol (E2), sex hormone-binding globulin (SHBG), and dihydrotestosterone (DHT). The data were modeled using multiple logistic regression with adjustment for age, height, body mass index (wt/ht2), years of schooling, and mutually among hormones. DHT was associated inversely, significantly, and strongly with the risk of prostate cancer, whereas T was associated marginally positively, and E2 was associated nonsignificantly inversely with the disease. No association was observed in this study with respect to SHBG.

Aged↗

PubMed1996

Life-style factors and medical conditions in relation to esophageal cancer by histologic type in a low-risk population.

A case-control study of esophageal cancer was conducted in Athens, Greece, during the 3-year period 1989-1991. Cases were 43 patients with incident esophageal squamous-cell carcinoma and 56 patients with incident esophageal adenocarcinoma hospitalized in any one of the 9 major hospitals in Athens, whereas controls were 200 injury patients admitted to the only Athens accident hospital. The data were analyzed by modeling through multiple logistic regression. Tobacco smoking and alcohol drinking were associated with both histologic types, but the odds ratios were generally lower than those observed in several other investigations. It may be that the high consumption of vegetables and fruits by the Greek population cushions the deleterious effect of tobacco, while the intake of ethanol in the form of wine during meals reduces the impact of this substance on the esophageal mucosa. A preference for very hot temperature for beverages and food was associated with significant elevation of the odds ratio to about 1.8 for esophageal cancer in general. There was non-significant evidence in our data to support earlier reports that aspirin intake may reduce the risk of cancer of the esophagus. Overall, we found no striking difference in the risk profile of the 2 histologic types of esophageal cancer.

Aged↗

PubMed1996

Diet and risk of esophageal cancer by histologic type in a low-risk population.

In a hospital-based case-control study of esophageal cancer undertaken in Athens (1989-1991), 43 patients with incident esophageal squamous-cell carcinoma and 56 patients with incident esophageal adenocarcinoma were compared to 200 injury patients. Personal interviews were conducted in the hospital setting, and dietary intake was assessed using a validated semi-quantitative food-frequency questionnaire. Nutrient intakes for individuals were calculated by multiplying the nutrient content of a typical portion size for each specified food item by the frequency with which the food was consumed per month and summing these estimates for all food items. Data were modeled through logistic regression, controlling for socio-demographic factors, tobacco smoking, consumption of alcoholic beverages and total energy intake. Consumption of vegetables and fruits as well as intake of vitamin A, vitamin C and crude fiber were inversely associated with esophageal cancer in general, but the respective associations were stronger for adenocarcinoma. There was evidence that added oils and fats and intake of polyunsaturated fat were positively associated with adenocarcinoma but inversely associated with squamous-cell carcinoma.

Adenocarcinoma↗

PubMed1996

Perinatal characteristics in relation to incidence of and mortality from prostate cancer.

OBJECTIVE: To test the hypothesis that factors causing morbidity and mortality from prostate cancer may operate in utero. DESIGN: Matched case-control study of singleton men born between 1874 and 1946 at one hospital. SETTING: Uppsala University Hospital. SUBJECTS: 250 patients with prostate cancer and 691 controls, including 80 patients who died from prostate cancer and their 196 matched controls. MAIN OUTCOME MEASURES: Mother's age at menarche, parity, pre-eclampsia or eclampsia before delivery, age at delivery and socioeconomic status; case or control's birth length and weight, placental weight, prematurity derived from gestational age, and presence of jaundice. RESULTS: Both pre-eclampsia (odds ratio 0, 95% confidence interval 0 to 0.71) and prematurity (0.31, 0.09 to 1.04) were inversely associated with incidence of prostate cancer. Among subjects born full term, placental weight, birth weight, and ponderal index (weight/height 3) showed non-significant positive associations with prostate cancer incidence, and stronger associations with mortality. CONCLUSION: Prenatal exposures that are likely correlates of pregnancy hormones and other growth factors are important in prostate carcinogenesis and influence the natural course as well as the occurrence of this cancer.

Age Factors↗

PubMed1996

A case-control study of lactation and cancer of the breast.

We have examined the relation of lactation, by total duration, with breast cancer risk among pre- and post-menopausal women. In a hospital-based case-control study conducted in Athens (1989-91), involving 820 patients with confirmed breast cancer and 795 orthopaedic patient controls and 753 hospital visitor controls, logistic regression was used to analyse the data controlling for demographic, nutritional and reproductive factors, including parity and age at any birth. Among post-menopausal women, there was no association between breastfeeding and breast cancer risk, but among premenopausal women those who has breastfed for > or = 24 months had an odds ratio of 0.50 (95% confidence interval 0.23-1.41). A reduction of the odds ration was also evident among premenopausal women who had breastfed between 12 and 23 months (odds ratio 0.70; 95% confidence interval 0.34-1.60). In conjunction with several other recent reports these results support the hypothesis that breastfeeding of prolonged duration may reduce the risk of breast cancer among premenopausal women but not among post-menopausal women. The biology underlying this different effect remains unknown, and the practical implication of the finding is a marginal importance.

Breast Feeding↗