Search PubMed⌕ Search

Biomedical subjects

W H Chow

Publications and source records attributed to W H Chow.

At least 127 records · Page 7Linked to original sources
PubMed1995

Cancer risk following polymyositis and dermatomyositis: a nationwide cohort study in Denmark.

Polymyositis and dermatomyositis (PM/DM) have been associated with cancer, although the long-term risks are poorly understood. To evaluate the risk of cancer by time periods subsequent to PM/DM diagnosis, a cohort of 539 patients hospitalized with PM/DM in Denmark between 1977 and 1989 was identified from the Danish Central Hospital Discharge Register. Cancer incidence among cohort members was ascertained by linkage to the Danish Cancer Registry using a unique personal-identification number. The overall cancer risk was elevated significantly among patients with DM (standardized incidence ratio [SIR] = 3.8, 95 percent confidence interval [CI] = 2.6-5.4) and to a lesser extent PM (SIR = 1.7, CI = 1.1-2.4). Significant excesses were observed for cancers of lung, ovary, and lymphatic and hematopoietic system. However, the excess cancer incidence declined steadily with increasing years since initial diagnosis of PM/DM. The cancer risk was increased about sixfold (SIR = 5.9, CI = 3.8-8.7) during the first year, but was lower during the second year (SIR = 2.5, CI = 1.1-4.8), with no significant excesses in subsequent years of follow-up. These findings confirm that PM/DM may occur as a paraneoplastic syndrome that calls for steps aimed at early cancer detection and treatment. Among long-term survivors of PM/DM, however, there is little evidence to warrant extensive preventive and screening measures beyond those recommended for the general population.

Adult↗
PubMed1995

Smoking and biliary tract cancers in a cohort of US veterans.

Except for gallstones, the risk factors for cancers of the biliary tract (CBTs) are poorly understood. Recent case-control studies have suggested cigarette smoking as a potential risk factor. In a cohort study of nearly 250,000 US veterans whose mortality was followed for up to 26 years, we evaluated the risk of CBT associated with tobacco use. Relative risks (RRs) and corresponding 95% confidence intervals (CIs) were calculated. A total of 303 CBT deaths were observed during the follow-up period. Compared with those who had never used any tobacco, current cigarette smokers at entry to the cohort had a 50% excess risk of CBT (RR = 1.5, CI = 1.1-2.0). A nearly 2-fold risk was observed among those who smoked more than 20 cigarettes per day and among those who started smoking under age 20. Non-significant increases in risk occurred among smokers of other forms of tobacco. This cohort study is consistent with reports that smoking is a risk factor for CBT, but further studies are needed to clarify whether the effect is specific for certain subsites and whether it reflects an association with pre-existent gallstones.

Adult↗
PubMed1995

Fine-needle aspiration cytologic diagnosis of lymphoepithelioma-like carcinoma of the lung. Report of two cases with immunohistochemical study.

Lymphoepithelioma is a term used to describe an undifferentiated carcinoma with prominent lymphoid infiltration in the nasopharynx. Recently, tumors with similar histology, designated as lymphoepithelioma-like carcinomas, have been described in other sites including the lung. The authors report two cases of pulmonary lymphoepithelioma-like carcinoma that were correctly diagnosed by fine-needle aspiration cytology. The distinctive cytologic features consist of cohesive sheets and clusters of spindle tumor cells, which possess moderately pleomorphic vesicular nuclei and prominent nucleoli that are intimately intermixed with numerous small lymphocytes. Immunohistochemical study, performed on the cell block preparation, revealed strong positive staining of these tumor cells for epithelial markers. In both cases, the cytologic diagnosis were confirmed subsequently by histologic examination of the resected surgical specimens. Cytologically, the differential diagnoses include granulomatous inflammatory diseases (especially tuberculosis), malignant lymphoma, melanoma, and metastatic sarcoma. The characteristic cytology of the tumor cells, together with their pattern of immunohistochemical staining, are helpful to distinguish lymphoepithelioma-like carcinoma from the differential diagnoses. In these cases, careful examination of the nasopharynx, preferably with multiple random mucosal biopsies, is essential for the exclusion of nasopharyngeal undifferentiated carcinoma because of the obvious differences in treatment and prognosis.

Aged↗
PubMed1995

Occupational risks for cutaneous melanoma among men in Sweden.

A population-based linked-registry was used to evaluate incidence of malignant melanoma of the skin among Swedish men by industry and occupation. There were 3850 cutaneous melanoma cases identified in the 19-year follow-up of men employed in 1960. New associations were observed for men employed in the breweries and malt-processing industry and in shoe fabrication from leather and skins. Several findings supported associations previously reported in other countries, including an excess risk among workers in basic chemical production and the printing industry and among professional, technical, and white-collar workers. Risk overall was not increased among farmers, despite a significant excess of melanoma of the face, neck, and scalp. Although this linked registry analysis lacked information about specific agents, duration of employment, and occupational and recreational sun exposures, it did provide leads for new associations and confirmed previous ones. Nevertheless, because of these limitations, etiologic clues must be interpreted cautiously.

Adolescent↗
PubMed1995

An unusual case of asymptomatic aplastic renal dysplasia.

The postmortem examination of a 59-year-old man who had suffered from acute abdominal pain for two days revealed that the cause of death was peritonitis secondary to perforated peptic ulceration. During examination, it was found that the urinary tract was abnormal. Here, we report a postmortem finding of aplastic renal dysplasia of the kidney and malformation of the urinary tract.

Humans↗
PubMed1995

Risk of renal cell cancer in relation to diuretics, antihypertensive drugs, and hypertension.

Although recent data have suggested an association between renal cell cancer and the use of diuretics, it remains unclear whether these medications or hypertension is the important risk factor. In a population-based case-control study including 440 renal cell cancer cases, spouses of an additional 151 cases, and 691 controls, we assessed renal cell cancer risk associated with hypertension and use of diuretics and other antihypertensive medications. Risks increased with the use of diuretics or other drugs that lower blood pressure, especially among persons who reported no history of hypertension. After adjustment for hypertension, the use of diuretics alone was associated with a 40% excess risk (OR = 1.4; 95% CI = 0.8-2.2), while use of other antihypertensive drugs was linked to a 2-fold risk (OR = 2.0; 95% CI = 1.2-3.3). The excess risk was not restricted to any specific products, and no trend was observed with estimated lifetime consumption of any product. Furthermore, risk was not potentiated by the presence of both hypertension and the use of antihypertensive drugs. Among persons who did not use antihypertensive drugs, a history of hypertension was associated with a significant 40-50% excess risk of renal cell cancer. Excluding subjects with hypertension diagnosed within 5 years of cancer diagnosis or interview had only a small effect on risk. These findings suggest small effects on renal cell cancer risk associated with hypertensive disease and with the use of diuretics and other antihypertensive drugs, but it is difficult to disentangle the separate effects due to potential misclassification of highly correlated events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Dietary factors and the risk of pancreatic cancer: a case-control study in Shanghai China.

In Shanghai, China, age-adjusted incidence rates for pancreatic cancer have increased steadily, beginning in the early 1970s. To examine the effects of diet on this cancer, a population-based case-control study was conduct. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990 and June 30, 1993. Decreased cases (19%) were excluded from the study. Controls (n = 1552) were selected among Shanghai residents, frequency matched to cases by gender and age. Information on usual adult dietary intake was obtained by trained interviewers in person, using a food frequency questionnaire. Dietary associations were measured by odds ratios and 95% confidence intervals. Risks of pancreatic cancer were inversely associated with consumption of vegetables (P for trend among men = 0.03; among women = 0.15) and fruits (P among men = 0.02; among women = 0.08). Reductions in risk were related also to intake of dietary fiber and micronutrients abundant in plant sources, such as vitamins C and E and carotene. There was also an inverse association with egg consumption (P for trend among men = 0.08; among women = 0.001). No consistent positive associations were observed with intake of other food groups, including preserved animal foods, fresh red meat, organ meat, poultry, and staple foods. On the other hand, risks increased with frequency of consumption of preserved vegetables and foods that were deep fried, grilled, cured, or smoked, providing clues to the possible role of nitrosamines, polycyclic aromatic hydrocarbons, and heterocyclic aromatic amines. The inverse associations observed with intake of dietary fat and protein in our study were unexpected, although these findings were based on consumptions well below the average intake in Western countries, where most previous studies on pancreatic cancer were conducted. Our results suggest that dietary variations have contributed little to the rising trends of pancreatic cancer in Shanghai. However, given the improving food availability and changing dietary patterns in China, further study of dietary and nutritional risk factors for pancreatic cancer appears warranted.

Adult↗
PubMed1994

Use of analgesics and risk of renal cell cancer.

Although heavy or long-term use of analgesics has been related to risk of renal cell cancer in several studies, evidence for such an association remains inconclusive. In a population-based case-control study including 440 renal cell cancer cases, spouses of an additional 151 cases, and 691 controls, we assessed renal cell cancer risk associated with lifetime consumption among those who reported during in-person interviews regular (at least 2 or more times per week for 1 month or longer) use of analgesics. Odds ratios (OR) were computed using logistic regression analyses. No excess risk was associated with regular use of aspirin, acetaminophen, phenacetin or combinations of these agents, nor did risks rise with increasing cumulative intake of these analgesics. A non-significant increased risk (OR = 2.1, 95% CI = 0.6-6.9) was observed among women who used only acetaminophen-containing analgesics, but little excess was seen in men. Earlier studies reported a link to phenacetin-containing analgesics, but no one reported exclusive use of phenacetin-containing drugs in our study. The findings suggest that use of analgesics is not likely to play a major role in renal cell cancer development and that for cases diagnosed in the late 1980s or later, after the earlier withdrawal of phenacetin-containing drugs from the market, a hazard from this analgesic no longer exists.

Acetaminophen↗
PubMed1994

Protein intake and risk of renal cell cancer.

BACKGROUND: Renal cell cancer, although still relatively uncommon, has been increasing in incidence in the United States and other countries around the world. PURPOSE: Since previous studies have suggested an association with high intake of meat, we sought to further examine the role of diet in renal cell cancer risk. METHODS: Patients with histologically confirmed renal cell cancer that had been diagnosed between July 1, 1988, and December 31, 1990, were identified through the Minnesota Cancer Surveillance System, a statewide cancer registry. The patients eligible for inclusion in this study were white residents of Minnesota between 20 and 79 years of age. Control subjects were selected from the general population of Minnesota residents; subjects under age 65 were selected by use of a random-digit-dialing method and those 65 years or older were sampled from the Health Care Financing Administration files. Population-based control subjects were frequency-matched to cases by sex and 5-year age groups. A total of 690 patients and 707 control subjects were interviewed. Patients and control subjects were similar in distribution by sex, age, and educational level. Usual adult dietary intakes were assessed by questionnaire, and odds ratios were calculated by logistic regression analyses. RESULTS: Significantly increased risks of renal cell cancer were observed with increasing consumption of several food groups, including red meat (P for trend = .05), high-protein foods (P = .01), and staple (grains, breads, and potatoes) foods (P = .009). When examined by macronutrient status, risks increased monotonically with the amount of protein intake, from 1.2 (95% confidence interval [CI] = 0.7-1.9) to 1.4 (95% CI = 0.8-2.5) and 1.9 (95% CI = 1.0-3.6) (P for trend = .03) in the second, third, and fourth quartiles of intake, respectively, after adjustment for age, sex, caloric intake, body mass index, and cigarette smoking. No significant or consistent associations were detected with the intake of other dietary nutrients or beverages. CONCLUSION: Although an independent effect of dietary protein has not been previously associated with renal cell cancer, high protein consumption has been related to development of other chronic renal conditions that may predispose an individual to this cancer. IMPLICATION: These findings should prompt further study of dietary protein and its potential contribution to the origins of renal cell cancer.

Adult↗
PubMed1994

Temporal patterns in colorectal cancer incidence, survival, and mortality from 1950 through 1990.

BACKGROUND: Colorectal cancer mortality rates among U.S. white males remained relatively constant from 1950 through 1984 but declined sharply from 1985 through 1990. Those for U.S. white females decreased consistently from 1950 through 1984, with an acceleration of the decline from 1985 through 1990. PURPOSE: A study was planned to investigate patterns in incidence, survival, and mortality rates over time in order to examine possible reasons for the gender difference in mortality trends and for the decrease in the slope of the mortality trends for both males and females in the late 1980s. METHODS: Incidence and survival data from the Connecticut Cancer Registry were examined to investigate the gender differences in mortality rates from 1950 through 1984. Incidence and survival data from the Surveillance, Epidemiology, and End Results (SEER) Program were investigated to examine reasons for the abrupt downturn in mortality rates for both white males and white females beginning around 1985. RESULTS: During the period 1950 through 1984, the colorectal cancer incidence rates in Connecticut increased for males and declined slightly for females. Survival rates were similar for both sexes, increasing on average over 1% per year for both females and males from 1950 through 1984. Examination of SEER data from 1975 through 1990 revealed that for both males and females there were 1) declines in overall incidence and mortality rates beginning in the mid-1980s, 2) steady declines in distant disease incidence rates since 1975, 3) increases in regional disease incidence rates until the early 1980s followed by declines in the late 1980s, and 4) increases in local disease incidence rates until the mid-1980s followed by declines in the late 1980s. Age-period-cohort analyses of mortality rates indicated a statistically significant moderation of colorectal cancer risk with both advancing birth cohorts and recent calendar periods. CONCLUSIONS: The gender differences in colorectal cancer mortality rate trends observed from 1950 through 1984 are due to differences in incidence rate trends between males and females. Declining colorectal mortality rates in the late 1980s for males and females appear to reflect improved early detection. The peaking and subsequent decline of stage-specific incidence rates at later years for successively lower stage indicate sequential stage shifts as cancers are detected increasingly earlier over time. The increased use of sigmoidoscopy and fecal occult blood tests (triggering colonoscopy) appears to have played an important role in reducing colorectal cancer mortality. Improvements in birth cohort trends in risk for colorectal cancer for each sex suggest that lifestyle changes may have also contributed to the steady reductions in colorectal cancer mortality.

Adult↗
PubMed1994

Cohort study among workers exposed to benzene in China: I. General methods and resources.

Benzene is recognized internationally as a leukemogen, but the available data to clarify dose-response relationships and examine risks of malignancies other than leukemia are sparse. A collaborative study was therefore carried out to expand on a previous retrospective cohort mortality study of Chinese benzene-exposed workers. Methods and resources used in the 16-year follow-up of 74,828 benzene-exposed and 35,805 unexposed workers employed for any length of time during 1972-1987 in 712 factories in 12 cities in China are described. Details are provided of the study organization, assessment of benzene exposures since 1949, characterization of factories and workers by exposure status, city, and sex, identification and confirmation of cancers and other deaths, and quality control procedures. The distinguishing features of the study are discussed in relation to earlier cohort studies, and study limitations as well as strengths are presented.

Adult↗
PubMed1994

Cohort study among workers exposed to benzene in China: II. Exposure assessment.

This report describes a retrospective exposure assessment method used in a follow-up mortality study of workers exposed to benzene. The approach quantified historical exposure to benzene in a multi-industry, multicenter cohort, involving 672 factories in 12 cities in China. Historical exposure data were collected to obtain exposure information related to 1,427 work units (departments) and 3,179 unique job titles from benzene-producing or -using factories in which written records and other data sources were evaluated. The basic unit for exposure assessment was a factory/work unit/job title combination which was considered separately during each of seven calendar-year time periods between 1949 and 1987 for a total of 18,435 exposure assignments. Historical information collected to estimate exposure included benzene monitoring data; lists of raw materials and factory products, and the percentage of benzene in each; the total amount and dates of use of benzene or benzene-containing materials; use of engineering controls and personal protective equipment; and other available exposure information. Overall, 38% (ranging from 3% for the earliest periods to 67% for the last period) of the estimates were based primarily on benzene monitoring data. In the absence of job-specific benzene monitoring data for a given calendar period, measurement results or exposure estimates for similar jobs and/or other calendar periods were used in conjunction with other exposure information to derive estimates. Estimated exposure levels are presented by industries and occupations. The highest average exposures during 1949-1987 were observed for the rubber and plastic industry (30.7 ppm), and for rubber glue applicators (52.6 ppm).

Benzene↗
PubMed1994

Occupation and stomach cancer in a cohort of Swedish men.

Using the Cancer-Environment Registry of Sweden, which links the 1960 census information on employment with cancer incidence data from 1961-1979, we conducted a systematic, population-based assessment of stomach cancer incidence by industry and occupation for men in Sweden. Nearly 17,000 stomach cancer cases were diagnosed during the 19 years of follow-up. Stomach cancer incidence was elevated among miners and quarrymen, farmers and fishermen, and craftsmen and production workers. Men who held white collar jobs, including professional and technical, administrative and management, clerical, and sales jobs, had a reduction in stomach cancer incidence. Examination of specific jobs revealed generally elevated rates of stomach cancer among men who may be exposed to dusty work environments, such as quarry workers, stone cutters, circular and plane operators, construction workers, crane operators, heavy laborers, and shop and construction metal workers. These occupational associations mostly were observed for stomach cancers of noncardia origin, and no significant associations were found with cardia cancers. We had no information on dietary or other potential confounding factors and cannot make inferences about the role of occupation per se, but the current findings support those of earlier investigations and add to the evidence of a small but significant occupational role in stomach carcinogenesis.

Dust↗
PubMed1994

Risk factors for extrahepatic bile duct cancers: Los Angeles County, California (USA).

Extrahepatic bile duct (EBD) cancers are rare and their risk factors are poorly understood. Except for a history of gallbladder diseases, evidence for other potential risk factors, such as excess body weight and use of tobacco and alcohol, is scant. A case-control study was conducted to examine risk factors for EBD cancers, including ampulla of Vater tumors, among Los Angeles County (California, USA) residents. Included were 105 histologically confirmed cases diagnosed between 1 March 1985 and 31 October 1989, aged 30 to 84 years, and 255 population-based controls frequency-matched to cases by gender and age in five-year groups. Cases and controls were interviewed about their demographic background and potential risk factors, including tobacco, alcohol, and beverage consumption, diet, medical history, and reproductive factors among women. For deceased cases, their next-of-kin were interviewed. Risk of cancers of both subsites of extrahepatic duct and ampulla of Vater increased with smoking of cigars/pipes or cigarettes. For both men and women, risks increased twofold or more among those who smoked cigarettes for 50 or more pack-years. While a history of gallbladder diseases substantially increased the risk of cancers of both subsites, excess body mass index was associated only with cancer of extrahepatic duct subsite (odds ratio [OR] = 4.0, 95 percent confidence interval [CI] = 1.1-14.2 among men and OR = 2.7; CI = 0.8-9.4 among women in the highest quartile relative to those in the lowest quartile). Alcohol drinkers had lower risks compared with nondrinkers, but no consistent trend was observed with amount consumed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Diet and serum markers in relation to primary brain tumor risk in China.

Associations between primary brain tumor mortality and dietary habits, certain serum biochemical markers, and life-style factors were evaluated in a county-based correlation study utilizing data collected from an ecological survey in 49 Chinese rural counties. Univariate correlation and multivariate regression analyses showed that high consumption of salt-preserved vegetables was linked to increased primary brain tumor mortality rates, although the association was significant only among men. In addition, high intake of green vegetables among men was associated with decreased rates. No clear association was seen between primary brain tumor mortality rates and tobacco use, body mass index, and serum biochemical markers. Limitations of these ecological data preclude causal inferences, but the findings provide etiologic clues to primary brain tumor mortality in rural China.

Adult↗
PubMed1994

Cytologic features of Kimura's disease in fine-needle aspirates. A study of eight cases.

Kimura's disease is a chronic inflammatory disorder of unknown etiology, presenting usually as painless subcutaneous swellings in the head and neck region or in the salivary glands. The cytologic features of fine-needle aspirates of eight cases of Kimura's disease were studied with reference to the histologic appearance of the subsequent surgical specimens. In the cytologic smears, the prominent feature was the presence of significant numbers of eosinophils in a background of lymphoid cells. Fragments of collagenous tissue and Warthin-Finkeldey polykaryocytes occasionally were seen. In the cell block, vascular proliferation and fibrosis were useful features, providing further support to the diagnosis. The constellation of these features is characteristic of Kimura's disease and should suggest this diagnosis in the appropriate clinical setting. For initial diagnosis, excisional biopsy is important for the exclusion of malignant lymphoma, histiocytosis X, angiolymphoid hyperplasia with eosinophilia and other reactive lymphadenopathies. Nonetheless, fine-needle aspiration cytology may be valuable in the diagnosis of recurrent lesions of Kimura's disease and may spare the patient from repeated biopsies.

Adult↗
PubMed1994

Correlation of cervical cancer mortality with reproductive and dietary factors, and serum markers in China.

BACKGROUND: Cervical cancer is the second leading cause of cancer death among Chinese women. Within China, a considerable geographical variation in mortality rates has been observed, but the reasons are not well understood. METHODS: Cervical cancer rates were examined in relation to indices of reproductive factors, dietary habits, and selected serum biomedical markers in 65 rural Chinese counties. RESULTS: Cervical cancer mortality rates correlated positively and significantly with antibodies to herpes simplex virus type 2 (HSV-2) (r = 0.40, P < 0.01), serum levels of ferritin (r = 0.33, P < 0.01), body mass index (BMI) (r = 0.42, P < 0.01) and cigarette smoking (r = 0.51, P < 0.05) and negatively and significantly with age at first birth (r = -0.51, P < 0.01), consumption of green vegetables (r = -0.40, P < 0.01) and animal foods (r = -0.40, P < 0.01), and serum levels of selenium (r = -0.26, P < 0.05). When these variables were considered in the multiple regression analysis, early age at first birth and higher BMI were positively associated with cervical cancer mortality, while consumption of green vegetables and animal foods were negatively correlated. In the serum model, infection with HSV-2 and low levels of sex hormone binding globulin (SHBG) were positively related to cervical cancer mortality. No relation was found for consumption of fruits. CONCLUSIONS: Although limitations of these ecologic data preclude causal inferences, findings in this study, including associations with HSV-2 infection, early age at first birth, consumption of green vegetables and animal foods, may provide clues to cervical cancer aetiology.

Adult↗