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Biomedical subjects

J Yuen

Publications and source records attributed to J Yuen.

At least 37 records · Page 2Linked to original sources

Lifestyle and endometrial cancer risk: a cohort study from the Swedish Twin Registry.

Case-control studies of lifestyle factors have been inconclusive in the study of endometrial cancer, and prospective data are scarce. Our aim was to examine the associations of physical activity, weight and weight change, fruit, vegetable, and alcohol consumption, socio-economic status, parity and presence of diabetes mellitus with the risk of endometrial cancer in a cohort study. In 1967, 11,659 women in the Swedish Twin Registry, born 1886-1925, answered a 107-item questionnaire, including questions about diet, physical activity and other lifestyle factors. Complete follow-up through 1992 was attained through record linkage to the Swedish Cancer and Death Registers. The relative risks for endometrial cancer were estimated in proportional hazards models that adjusted confidence limits for correlated outcomes. We observed 133 incident cases of endometrial cancer in the cohort. There was no clear pattern of risk over strata of alcohol or fruit and vegetable intake, although the data suggest an increased risk with very low fruit and vegetable intake. Increasing physical activity markedly decreased the risk of endometrial cancer (p for trend < 0.01), independently of weight and parity; the risk in the highest quartile, relative to the sedentary category, was 0.2 (95% CI 0.3-0.8). As expected, higher weight in middle age increased the risk (p for trend < 0.01), as did higher weight in early adulthood. Contrary to previous findings, weight gain did not have an effect independent of weight at enrollment. We did not find a genetic component to endometrial cancer. Our results confirm that environmental factors are the most important, especially physical activity, parity, and weight in young and middle age.

Adult↗

Second primary cancers in patients with squamous cell carcinoma of the skin: a population-based study in Sweden.

We studied second primary cancer among 25,947 patients diagnosed with squamous cell carcinoma of the skin (SCC) in Sweden between 1958 and 1992. In total, 5,706 patients developed a second primary cancer at any site, compared with an expected number of 2,651 [standardized incidence ratio (SIR) = 2.15; 95% confidence interval (CI) = 2.10-2.21]. Men below 60 years of age at diagnosis of SCC had higher SIR (2.5; CI = 2.2-2.8) with the highest risk during the first year of follow-up (SIR = 9.2; CI = 6.9-12.2). If second primary SCC was excluded, the SIR was reduced to 1.30 (CI = 1.25-1.34); the relationships by sex, age and time since diagnosis remained similar. For skin cancer, the SIR for second SCC was markedly elevated (SIR = 15.6) and the risk of malignant melanoma was elevated 3-fold. Significantly increased risks were found for most second cancers in squamous cell epithelium: lip (SIR = 5.2), respiratory organs (SIR = 1.7), esophagus (SIR = 1.5), cervix uteri (SIR = 2.2), and vulva including vagina (SIR = 2.3). There was a generally increased risk of almost 2-fold for second cancer in hematopoietic or lymphoproliferative tissues. Slightly increased rates (SIR = 1.0-1.5) were seen for second tumors in digestive tissues. Finally, a high SIR (SIR = 5.5) was observed for second primary cancer in salivary glands. In conclusion, patients with SCC are at increased risk to develop new primary cancer, especially in skin, squamous cell epithelial and tobacco-related tissues. Common risk factors among the tumor types might explain our findings, however, an intrinsic susceptibility among SCC patients to develop cancer is also possible.

Age Distribution↗

Mortality and cancer incidence in biomedical laboratory personnel in Sweden.

BACKGROUND: The work in biomedical laboratories is associated with exposure to a mixture of known and potential chemical carcinogens, mutagens, and teratogens. Previous studies have suggested an excess of brain tumors and hematopoietic system malignancies as well as breast cancers in women. METHODS: This retrospective cohort study investigated the standardized mortality ratio (SMR) and the standardized incidence ratio (SIR) for cancer in biomedical research laboratory personnel in Swedish universities 1970-1992. The cohort comprised 5,035 laboratory and, as an internal reference group, 2,923 nonlaboratory employees. RESULTS: The overall death rate was lower in both groups than in the general population. The SIR for brain tumors among male laboratory workers was 1.69 (0.62-3.68) and among male laboratory scientists, after more than 10 years of work (4 cases), it was 3.11 (0.85-7.56). There was an elevated SIR for malignant melanoma among female scientists in laboratories (3.51, 0.96-8.98) and for male scientists in nonlaboratory departments (2.86, 1.05-6.22). The SIR for breast cancer among female laboratory scientists was 1.62 (0.78-2.98). CONCLUSIONS: The present findings lend some support to an excess of brain tumors among male scientists and of breast cancer in female scientists in biomedical research laboratories.

Adult↗

Utilization of muscle flaps in the treatment of bronchopleural fistulas.

This paper reports the results of a series of 5 patients who underwent closure of persistent bronchopleural fistula using extrathoracic muscle flaps over a 6-year period. All patients had failed more conservative treatment. The surgeries were one- or two-stage procedures performed with the collaboration of cardiovascular and reconstructive surgical staffs. There were no associated mortalities. The muscle flaps utilized were the latissimus dorsi, serratus anterior, pectoralis major, pectoralis minor, and trapezius. The results have been encouraging and allowed the complete closure of the bronchopleural fistula in the majority of patients. The authors present the best management of this serious disease, as well as its pathophysiology and clinical aspects.

Adult↗

Protective effect of fruits and vegetables on stomach cancer in a cohort of Swedish twins.

Observational studies, primarily of a case-control design, have shown an inverse association of fruit and vegetable consumption with the risk of stomach cancer, a finding tentatively attributed to anti-oxidant vitamins. Ensuing randomized-intervention trials of these vitamins, however, have been mostly negative. Therefore, the seemingly protective effect of fruit and vegetables in case-control studies is suspected to be influenced by the information bias inherent in the retrospective assessment of exposure, particularly since pre-conceptions about the wholesome effects of these foods are common among the public. Our aim was to examine the association of fruit and vegetable intake with the risk of stomach cancer in a prospective cohort study. Fruit and vegetable consumption was assessed in 1967 in 11,546 individuals in the Swedish Twin Registry, along with a wide range of potentially confounding factors. Complete follow-up through 1992 was attained through record linkage to the National Cancer and Death Registers. The relative risk of stomach cancer was estimated in proportional hazards models, with confidence intervals (CIs) adjusted for correlated outcomes. The risk of stomach cancer was inversely related to fruit and vegetable consumption. Controlling for potentially confounding factors, the relative risk among subjects with the lowest compared to those with the highest intake was 5.5 (95% CI 1.7-18.3) with a statistically significant dose-risk trend (p < 0.05). Our results indicate that information bias is not likely to explain the discrepancy between the results of observational studies and of randomized-intervention trials.

Aged↗

Low cyanide exposure from consumption of cassava in Dar es Salaam, Tanzania.

The extent of cyanide exposure from cassava consumption was studied in low income suburbs of Dar es Salaam, Tanzania. Mean cyanogen levels in sun-dried root pieces called makopa was 9.4 (range 0-79) mg HCN equivalents kg(-1) dry weight. The mean glucoside and hydrogen cyanide levels were 6.4 and 3.2 mg HCN equivalents kg(-1) dry weight, respectively, while cyanohydrins were lower with a mean of 2.0 (range 0-27) equivalents kg(-1) dry weight. Food frequency interviews with 193 schoolchildren revealed that 13% of the children consumed cassava stiff porridge in the previous week. Fried cassava pieces were consumed by 82% and boiled cassava pieces by 49% of the children. The urinary thiocyanate in these children was 36 +/- 3 (mean +/- SEM) micromol l(-1) and mean urinary linamarin level was 18 +/- 1 micromol l(-1), indicating low cyanide exposure. Multiple regression analysis revealed a positive correlation between urinary thiocyanate and consumption of boiled cassava pieces as well as between urinary linamarin levels and daily intake of fried cassava pieces.

Adolescent↗

Dairy products, calcium, phosphorous, vitamin D, and risk of prostate cancer (Sweden)

OBJECTIVES: Dairy products consistently have been associated with an increased risk of prostate cancer, yet the mechanism of this relationship remains unknown. Recent hypotheses propose that 1,25 dihydroxyvitamin D (1,25 D) is protective for prostate cancer. One study in the United States found that calcium consumption, which can lower circulating 1,25 D, was associated with higher risk of advanced prostate cancer, and we sought to address this hypothesis in a distinct population. METHODS: We analyzed data from a population-based case-control study of prostate cancer conducted in Orebro, Sweden, with 526 cases and 536 controls. Using unconditional logistic regression models, we examined the relationship of dairy products, dietary calcium, phosphorous, and vitamin D with risk of total, extraprostatic, and metastatic prostate cancer. RESULTS: Calcium intake was an independent predictor of prostate cancer (relative risk (RR) = 1.91, 95 percent confidence interval (CI) 1.23-2.97 for intake > or = 1183 vs. < 825 mg/day), especially for metastatic tumors (RR = 2.64, 95 percent CI 1.24-5.61), controlling for age, family history of prostate cancer, smoking, and total energy and phosphorous intakes. High consumption of dairy products was associated with a 50 percent increased risk of prostate cancer. CONCLUSIONS: Our results support the hypothesis that high calcium intake may increase risk of prostate cancer, and this relation may underlie previously observed associations between dairy products and prostate cancer.

Adult↗

Muscle and musculocutaneous flap coverage of exposed spinal fusion devices.

Midline wound dehiscence in the back with exposure of spinal stabilization devices remains a challenging problem, mainly in the presence of infection. Usually, the treatment consists of instrumentation removal, wound debridement, and antibiotic therapy. These can result in instability of the spine and significantly prolong the hospitalization. The use of muscle and musculocutaneous flaps provides excellent soft-tissue coverage, obliterates the dead space, controls the infection, and creates conditions to salvage the hardware. Eight cases of spinal rod instrumentation, complicated by wound infection and dehiscence, have been treated successfully with single or multiple muscles and musculocutaneous flaps. Our method of treatment for these complex wounds, in two institutions, is discussed.

Adult↗

Factors associated with atypical nevi: a population-based study.

We conducted a case-control study to identify factors associated with the presence of clinically atypical nevi. Potential participants were selected, using a two-staged sampling scheme, from a population-based cohort of 50,000 Swedish women who had responded to a previous health survey questionnaire. Of 500 women sampled for study recruitment, 400 (80%) agreed to participate. Study participants underwent a physician-conducted skin examination, which identified 130 women who had at least one clinically atypical nevus (cases) and 270 women without these lesions (controls). The physician-conducted skin examination also assessed women for benign nevus counts; other risk factor information was based upon responses to a health survey questionnaire. We found a strong and highly statistically significant relationship between number of benign nevi and the presence of at least one clinically atypical nevus (P < 0.0001). Women with 100 or more benign nevi had a 26-fold increased likelihood of having an atypical nevus. We noted statistically significant interactions between number of benign nevi and other factors of interest; thus, the results are reported separately for women with low (<50) or high (> or =50) counts of benign nevi. Among women with low counts of benign nevi, the likelihood of having an atypical nevus increased with degree of freckling; there was also a suggested role for early sun exposure. Among women with high counts of benign nevi, difficulty tanning and lack of peeling sunburns between ages 10 and 19 appeared to increase the likelihood of case status; our data also suggested an inverse relationship between parity and atypical nevi in this subgroup.

Adult↗

Cancer risk among Scandinavian immigrants in the US and Scandinavian residents compared with US whites, 1973-89.

Studies of migrants can generate hypotheses on the aetiology of cancer. Such studies are most informative when cancer incidence data are available both in the source and host country. We compared the incidence rate ratio of cancers (stomach, lung, female breast, colorectal and prostate) in Scandinavian immigrants to the US to US-born whites, using data from the SEER registry, 1973-89. Odds ratios (OR) for cancer sites in relation to birthplace were estimated using logistic regression. We also compared rate ratios (RR) for Scandinavian and US residents, using Poisson regression. Compared with US whites, most Scandinavian migrant groups had elevated OR for stomach cancer (1.58 to 3.92), and lower OR for lung cancer (0.38 to 0.88). Similarly, compared with US whites, residents of most Scandinavian countries had elevated RR for stomach cancer (1.47 to 3.33) and lower RR for lung cancer (0.27 to 0.97). Therefore, risk factors for lung and stomach cancers, such as smoking habits and Helicobacter pylori infection, respectively, may have been retained upon migration. Risks for breast, colorectal and prostate cancer among immigrants approached risks in the US (contrasting Scandinavian risks) suggesting assimilation of environmental and/or lifestyle factors.

Adolescent↗

The paradoxical effect of smoking in preeclamptic pregnancies: smoking reduces the incidence but increases the rates of perinatal mortality, abruptio placentae, and intrauterine growth restriction.

OBJECTIVES: Smoking is associated with a reduced risk of preeclampsia, but what is the outcome of pregnancy when preeclampsia develops in women who smoke? STUDY DESIGN: Single births in Sweden from 1987 through 1993 to nulliparous women aged 15 to 34 years (N = 317,652) were included. Poisson regression analyses were used to calculate adjusted relative risks and rates of adverse pregnancy outcomes. RESULTS: Maternal smoking was associated with significantly reduced risks of mild and severe preeclampsia (relative risks = 0.6 and 0.5, respectively). In pregnancies with severe preeclampsia, smoking at least 10 cigarettes per day was associated with increased rates of perinatal mortality (from 24 to 36 per 1000), abruptio placentae (from 31 to 67 per 1000), and being small for gestational age (from 28% to 68%), whereas the corresponding smoking-related increases in rates in nonhypertensive pregnancies were considerably less. CONCLUSIONS: Smokers in whom preeclampsia develops have very high risks of perinatal mortality, abruptio placentae, and small-for-gestational-age infants.

Abruptio Placentae↗

Hormone replacement therapy and major risk factors for reproductive cancers, osteoporosis, and cardiovascular diseases: evidence of confounding by exposure characteristics.

Observational studies have yielded reports on long-term effects of hormone replacement therapy (HRT) for cardiovascular, osteoporosis-related, and cancer diseases. There is concern that risk estimates may be confounded by complex mechanisms of selection with regard to important risk determinants. In this study, we tested the hypothesis that baseline characteristics of women vary with exposure characteristics, i.e., the choices of complying with prescriptions, using different compounds and regimens, and continuing intake long-term. We analyzed the prevalence of relevant risk factors and their relationships to characteristics of exposure among 11,211 Swedish women who had received prescription for HRT. Associations were studied through logistic regression, with comparisons of women with ever-use versus non-compliance, long-term (73+ months) versus short-term use (1-72 months), intake of conjugated estrogens versus estradiol compounds, and intake of estrogens only versus estrogens combined with progestins, respectively. We found that women denying intake of using HRT short-term had higher parity, earlier age at first birth and a lower prevalence of hysterectomy or oophorectomy than those complying or exposed long-term. A high level of education was associated with compliance and long-term exposure, and heavy physical exercise and high intake of food fibers were associated with compliance. Climacteric symptoms were associated with compliance, long-term intake and use of conjugated estrogens, whereas a history of oral contraceptive intake was associated with use of estrogens alone without progestins. We conclude that selection biases in studies of HRT effects are important and complex in that they may vary with the reported exposure. Our findings are important, as they point to the need for improved methods for measuring, in particular, factors linked to lifestyle and health behavior, in order to account more fully for confounding in the analyses of risk relationships.

Aged↗

Second cancers after medulloblastoma: population-based results from the United States and Sweden.

Medulloblastoma, one of the most common central nervous system (CNS) tumors in children, requires aggressive multimodality therapy including surgery, radiation therapy, and occasionally chemotherapy. Given its intensive treatment regimen and improved survival during the past 20 years, it is likely that a cohort of survivors will result who may incur consequences of therapy, including a second cancer. We used population-based data from the United States and Sweden to estimate risks of second neoplasms in patients with histologically confirmed medulloblastoma (n = 1,262). Overall, there was a 5.4-fold excess of second neoplasms (95 percent confidence interval = 3.3-8.4) based on 20 observed and 3.7 expected cancers. The second cancers occurred eight to 432 months after initial diagnosis (median, 73 months) with significantly elevated ratios for all intervals examined except for less than one year after initial diagnosis. Significantly elevated risks were seen for cancers of the salivary glands, cervix uteri, brain and CNS, thyroid gland, and acute lymphoblastic leukemia. Of the 15 second cancers with treatment data, seven occurred in the radiation field or within areas of scatter while two others may have been radiation-related. Although based on small numbers of second cancers, the results suggest that as survival increases, some patients with medulloblastoma will have an increased risk of a second cancer, particularly a radiation-related cancer. Thus, as survival improves, late-occurring consequences of diagnosis and treatment will need to be carefully assessed. Identification of patients hypersensitive to radiation therapy, such as those with Gorlin Syndrome, should also be attempted in order to reduce the sequelae from intensive radiation exposure.

Adolescent↗

Parental cancer and risk of papillary and follicular thyroid carcinoma.

In a population-based case-control study in the Uppsala-Orebro Health Care Region of Sweden, the histories of cancer among parents of 517 histologically confirmed cases of papillary and follicular carcinoma and of a similar number of sex- and age-matched controls were compared. The parental history of cancer was compiled through information from death certificates and from the nationwide Cancer Register. The incidence of malignancies in a cohort of parents of cases of thyroid cancer was also compared with the incidence in the whole Swedish population. A maternal history of cancer was more common among women with follicular carcinoma than among their controls (OR 2.11, 95% CI 0.96-4.67). Parents of probands with papillary carcinoma had an increased risk of thyroid cancer (OR 4.25, 95% CI 1.16-10.89), and mothers of probands with follicular carcinoma had an increased risk of stomach cancer (OR 3.65, 95% CI 0.99-9.35) compared with the general population. Cancer of the lung, breast, and pancreas were less common than in the general population. Familial cases of thyroid cancer were not limited to the papillary type. An inheritable pattern of carcinogenesis is possible for certain differentiated non-medullary thyroid cancers, but shared environmental exposures may also explain the parent-child associations of cancer in this study.

Adenocarcinoma, Follicular↗

Training improves endothelium-dependent vasodilation in resistance vessels of patients with heart failure.

The effects of physical training on endothelium-dependent vasodilation in skeletal muscle resistance vessels were investigated in patients with heart failure. Forearm blood flows (ml.min-1.100 ml-1) in response to brachial arterial administration of acetylcholine (5 x 10(-5) and 5 x 10(-4) M at 1 ml/min) and nitroglycerin (5 x 10(-6) and 5 x 10(-5) M at 1 ml/min) were determined by strain-gauge venous occlusion plethysmography before and after 8 wk of daily handgrip exercise in 12 patients with chronic heart failure. After 8 wk of daily handgrip exercise, the vasodilatory responses to acetylcholine significantly increased from pretraining values, i.e., 16.6 +/- 2.0 vs. 8.6 +/- 1.3 ml.min-1.100 ml-1 (P < 0.05) and 27.5 +/- 1.5 vs. 14.6 +/- 1.7 ml.min-1.100 ml-1 (P < 0.05), respectively, whereas the vasodilatory responses to nitroglycerin did not change. Handgrip exercise training appears to specifically enhance endothelium-dependent vasodilation in the forearm skeletal muscle circulation of patients with heart failure.

Acetylcholine↗

Population-based study of cancer risk and relative survival following sphincterotomy for stones in the common bile duct.

BACKGROUND: Endoscopic sphincterotomy was introduced in 1974 as a procedure for removing stones in the common bile duct. To assess the long-term risk of cancer and relative survival, all patients who underwent this procedure at six different hospitals between 1977 and 1985 were identified. METHODS: A total of 992 patients was identified and they were followed by linkage to the Swedish Death Registry and the Swedish Cancer Registry. RESULTS: At 1 year or more after sphincterotomy there was no increased risk of cancer in the liver, gallbladder, bile duct or pancreas (standardized incidence ratio 0.80, 95 per cent confidence interval 0.3-1.9). Relative survival was lowered slightly in the first year after sphincterotomy, but did not differ from that of the background population thereafter. CONCLUSION: Endoscopic sphincterotomy for stones in the common bile duct does not appear to affect the risk of cancer in the pancreas, liver or bile ducts, nor does it affect long-term survival.

Adult↗