Biomedical subjects

J Chang-Claude

Publications and source records attributed to J Chang-Claude.

83 records · Page 5Linked to original sources

PubMed1992

Human papillomavirus (HPV) infection, HIV infection and cervical cancer in Tanzania, east Africa.

The presence of HPV-DNA was determined in tumor biopsies of cervical-cancer patients and in cervical swabs of non-cancer patients from Tanzania, East Africa, by Southern blot hybridization and/or PCR. HPV types 16 and 18 were detected in 38% and 32%, respectively, of 50 cervical-carcinoma biopsies. A consensus primer PCR capable of detecting a broad spectrum of HPV types revealed the presence of HPV-DNA in 59% of 359 cervical swabs of non-cancer patients. Type-specific PCR showed that types 16 and 18 accounted for 13.2% and 17.5%, respectively, of all HPV infections. Therefore we concluded that HPV 18 is more prevalent in Tanzania than in any other geographical location so far reported. The strongest risk factors for the presence of any HPV-DNA in the 359 female non-cancer patients were young age and HIV infection. The epidemiology of HPV types 16 and 18 was found to differ from that of other HPV types, being associated in univariate analysis with trichomonas vaginalis infection, martial status (single/divorced), age at first intercourse, and young age at menarche. However, young age at menarche accounted for most of the effects of all other, variables in multivariate analysis. Of the non-cancer patients, 12.8% had antibodies against HIV I (no patient being severely symptomatic), and HIV infection was highly correlated with the presence of HPV-DNA, especially types 16 and 18. While HPV-DNA of any type was detectable 1.4-fold more often in HIV-positive patients than in HIV-negative patients, evidence of an infection with HPV types 16 or 18 was found 2.2-fold more often in the HIV-positive patients. The HIV-positive women did not show an increased rate of cervical cytological abnormalities as assessed by PAP staining of a single cervical smear, the overall rate of abnormalities being 2.8%. Furthermore, the age-adjusted prevalence of HIV antibodies was found to be considerably lower in 270 cervical-carcinoma patients (3% HIV-positive) in comparison with non-cancer patients. Thus there was no association observable between the prevalence of HIV infections and the frequency of cervical cytological abnormalities or cervical cancer in the setting of this cross-sectional study.

Cervix Uteri↗

PubMed1992

Life style and occupational risk factors for bladder cancer in Germany. A case-control study.

A hospital-based, case-control study of 531 male and 144 female matched pairs was conducted in Germany to analyze the role of nonoccupational and occupational risk factors in the etiology of tumors of the lower urinary tract (bladder cancer). Smoking of cigarettes was associated with an odds ratio (OR) of 3.6 for men and 3.2 for women, compared with not smoking and showed a significant dose- and time-response relationship for both sexes. Heavy pipe smoking significantly increased the risk (OR = 1.9 in men), and smoking of cigars did not alter the risk of bladder cancer. Controlling for smoking, a significantly twofold or more increase in risk was found for heavy consumption of coffee in both sexes and for heavy intake of beer in males. Increasing levels of total fluid intake were associated with increasing, smoking-adjusted risks in men. Significant associations were found for chronic infection of the lower urinary tract (OR = 1.8), familial history of bladder cancer (OR = 2.5), and frequent consumption of high fat meals (OR = 1.4) among men and for frequent consumption of canned food in both sexes (OR = 1.7 for males, 2.4 for females). With regard to occupational history, significantly elevated odds ratios were found for ever-employment in the printing (5.0), plastics and synthetics (2.6), rubber (2.5), mining (2.0), and dyestuffs (1.9) industries, for exposure to spray paints (2.9), zinc (2.3), chromium/chromate (2.2), oils (1.5), petroleum (1.4), stone dust (1.4) and metal dust/fumes (1.3), and for occupation as mining worker (2.0) and truck driver (1.8) among men. Multivariate logistic regression analysis showed significant contribution of coffee and beer drinking, ingestion of canned food, and familial occurrence of urothelial tumors to the risk of bladder cancer in men after accounting for the effects of tobacco smoking, occupational exposures, and a history of bladder infection. These other variables did not influence the risk attributable to occupational exposures.

Aged↗

PubMed1992

Mortality pattern of German vegetarians after 11 years of follow-up.

A cohort of 1,904 vegetarians and persons leading a health-conscious life-style in the Federal Republic of Germany was identified in 1978. After a follow-up of 11 years, mortality from all causes was reduced by one-half compared with the general population [the standardized mortality ratio (SMR) was 0.44 for men, 0.53 for women]. Among the 858 men, 111 deaths were observed, with 255 expected; among the 1,046 women, 114 deaths were observed, with 215 expected. The lowest mortality was found for cardiovascular diseases (SMR = 0.39 for men, 0.46 for women); in particular, for ischemic heart diseases, mortality was reduced to one-third of that expected. Cancer mortality was reduced by one-half in men (SMR = 0.48), but only by one-quarter in women (SMR = 0.74). The deficit in cancer deaths was mainly observed for lung cancer and gastrointestinal cancers in males and for gastrointestinal cancers in females. Deaths from diseases of the respiratory and digestive systems were also reduced by about 50%. An excess of deaths occurred only for anemia. When the strict and the moderate vegetarians were analyzed separately, the strongest differential was found for ischemic heart diseases, which were much less frequent among strict vegetarians for both sexes. Some nondietary factors, such as higher socioeconomic status, virtual absence of smoking, and lower body mass index, may also have contributed to the lower mortality of the study participants.

Body Mass Index↗

PubMed1992

Lung cancer mortality among workers in the European production of man-made mineral fibers--a Poisson regression analysis.

One hundred and eighty-one lung cancer deaths among workers during 301,085 person-years in European man-made mineral fiber production between 1930-1955 and 1982 were analyzed according to Poisson regression models including age, calendar period, country, and exposure variables. Time since first employment was the variable most strongly associated with lung cancer risk in both the rock-slag wool and glass wool subcohorts. Workers in the early technological phase were at higher risk than those in other categories, particularly in rock-slag wool production. No clear trend with duration of employment was suggested. No major changes occurred in the interpretation of the results when workers with less than one year of employment or less than 20 years since first exposure were excluded. The original results, based on analyses for standardized mortality ratios, were confirmed, and workers with a short duration of employment or a short time since first employment did not need to be excluded from the analysis.

Air Pollutants, Occupational↗

PubMed1992

Risk factors for HIV infection in gynaecological inpatients in Dar es Salaam, Tanzania, 1988-1990.

A prevalence of 12.8% for anti-HIV-1 and a prevalence of 16.8% for anti-syphilis antibodies was found in 359 gynaecological inpatients admitted in the Department of Gynaecology and Obstetrics, Muhimbili University College of Health Sciences from 1988 to 1990. The highest HIV prevalence (17.3%) was observed in the youngest age group (14-20 years), whereas the highest syphilis prevalence (22.2%) was found in the oldest age group (> 45 years). Infections with HIV and syphilis were both significantly associated with variables related to sexual behaviour, such as marital status, age at first intercourse and number of sexual partners in the past ten years. After adjustment for these common risk variables linked to sexual behaviour, syphilis infection was still associated with a more than twofold higher risk of HIV infection (odds ratio (OR) = 2.60, p = 0.02) and trichomonas vaginalis infection with a nearly threefold higher risk (OR = 2.96, p < 0.001). These data characterize patients at risk for HIV infection among inpatients of a gynaecological department in East Africa, and indicate that effective measures to prevent sexually transmitted disease may reduce HIV transmission.

Adult↗

PubMed1991

Risk of cancer for arc welders in the Federal Republic of Germany: results of a second follow up (1983-8).

An extended follow up of 1221 chromium and nickel exposed welders in the Federal Republic of Germany confirmed an increased relative risk of 1.6 for all cancers compared with an internal reference group of 1694 turners. In an external comparison an excess of deaths from malignant tumours compared with that expected from the national mortality rates was found (standardised mortality ratio (SMR) = 109), which was clearly related to both time since first exposure and duration of exposure. Mortality from lung cancer was increased among welders (SMR = 113) but also among turners (SMR = 108). The difference remained when the subgroups were compared according to smoking information. A large excess of mesothelioma as a cause of death could be attributed to exposure to asbestos. The significantly increased SMR seen for urogenital tumours and "other or unspecified tumours" showed, however, an inverse relation with time since first exposure. This and other inconsistencies in the analysis by type of welding do not permit conclusive statements. Thus a further extension of follow up seems warranted.

Follow-Up Studies↗

PubMed1991

A historical prospective study of European stainless steel, mild steel, and shipyard welders.

A multicentre cohort of 11,092 male welders from 135 companies located in nine European countries has been assembled with the aim of investigating the relation of potential cancer risk, lung cancer in particular, with occupational exposure. The observation period and the criteria for inclusion of welders varied from country to country. Follow up was successful for 96.9% of the cohort and observed numbers of deaths (and for some countries incident cancer cases) were compared with expected numbers calculated from national reference rates. Mortality and cancer incidence ratios were analysed by cause category, time since first exposure, duration of employment, and estimated cumulative dose to total fumes, chromium (Cr), Cr VI, and nickel (Ni). Overall a statistically significant excess was reported for mortality from lung cancer (116 observed v 86.81 expected deaths, SMR = 134). When analysed by type of welding an increasing pattern with time since first exposure was present for both mild steel and stainless steel welders, which was more noticeable for the subcohort of predominantly stainless steel welders. No clear relation was apparent between mortality from lung cancer and duration of exposure to or estimated cumulative dose of Ni or Cr. Whereas the patterns of lung cancer mortality in these results suggest that the risk of lung cancer is higher for stainless steel than mild steel welders the different level of risk for these two categories of welding exposure cannot be quantified with precision. The report of five deaths from pleural mesothelioma unrelated to the type of welding draws attention to the risk of exposure to asbestos in welding activities.

Europe↗

PubMed1991

Epidemiological study of precursor lesions of oesophageal cancer among young persons in Huixian, China.

A total of 538 subjects (354 males, 184 females) were investigated in a high-risk area for oesophageal cancer in China to provide large-scale data on the prevalence of chronic oesophagitis among persons below 25 years of age. The survey included an oesophagoscopy with guided biopsies and cytology, a physical examination, an interview and collection of a 10-ml blood sample and overnight urine. Histologically confirmed oesophagitis was found in 43.5% of male and 35.6% of female subjects. Mild and moderate oesophagitis was associated positively with consumption of burning hot beverages, family history of oesophageal cancer, frequent consumption of cottonseed oil, cigarette smoking, a clinical diagnosis of oral leukoplakia and seborrhoeic dermatitis; negative associations were seen with frequent consumption of fresh fruit, meat and eggs. A significantly higher level of urinary nitrate was found in the diseased group, but no difference was seen with regard to any of the N-nitrosamino acids measured.

Adolescent↗

PubMed1989

Precursor lesions of oesophageal cancer in young people in a high-risk population in China.

Young people (15-26 years) were selected from households in a population in China at high risk of oesophageal cancer on the basis of whether a case of oesophageal cancer had (166 participants) or had not (372 participants) occurred in a first-degree relative. In an endoscopic survey 43.5% of the male subjects and 35.9% of the female subjects showed histological signs of chronic oesophagitis. The presence of these precursor lesions was significantly associated in a multivariate logistic model with consumption of burning hot beverages, a family history of oesophageal cancer (including second-degree relatives), infrequent consumption of fresh fruit, and infrequent consumption of dietary staples other than maize.

Adolescent↗

PubMed1989

[Case-control study for the diagnosis of occupational factors in bladder cancer].

The occupations and life-style factors of 531 male bladder cancer patients were compared with matched hospital controls; risk estimates were obtained as odds ratios of discordant pairs. The case-control study as a "fishing approach" for occupational risk factors has proven successfully that established hazards for cancer could be confirmed (e g smoking, bladder infections, mining and chemical exposures), and others were identified for the first time in Germany (vehicle driving, spray painting, oil- and petroleum exposures). Not only could smoking-adjusted risk estimates be statistically confirmed but also trends of risk increasing with duration of occupational exposure were determined. Logistic regressions were performed to determine the influence of life-style factors on occupational risks.

Adult↗

PubMedDate not supplied

Micronuclei in esophageal cells of Chinese youths in a high-incidence area for esophageal cancer in China.

An epidemiologic survey among 538 young persons between 15 and 26 years of age in a high-risk area for esophageal cancer in the People's Republic of China revealed a high prevalence of esophagitis. Histologically confirmed very mild, mild, and moderate esophagitis was observed in 31.6%, 10.7%, and 1.1% of 354 male and 30.4%, 4.3%, and 1.1% of 184 female subjects. The prevalence of micronuclei in esophageal smears was assayed in a subsample to investigate its possible association with esophagitis and with risk factors for esophageal lesions. Of the 186 subjects, 2.7% had mild or moderate esophagitis, 19.9% had very mild esophagitis, and 77.4% were normal. The frequency distribution of micronucleated cells in the esophageal mucosa was similar for the three diagnostic groups. Mean percentages of micronucleated cells did not differ by diagnosis of esophagitis, household status, current smoking status, presence of oral leukoplakia, or consumption of burning hot beverages or fresh fruit. Higher mean percentages were observed in the older age group of both sexes, but the difference was not statistically significant. The results suggest that if esophagitis is considered an important precursor state in the development of esophageal cancer, the scoring of micronuclei does not appear to be an efficient test for mild forms of esophagitis.

Adolescent↗