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Biomedical subjects

H Austin

Publications and source records attributed to H Austin.

At least 19 recordsLinked to original sources
PubMed1992

Cigarette smoking and the incidence of cervical intraepithelial neoplasia, grade III, and cancer of the cervix uteri.

The relation between cigarette smoking and cervical intraepithelial neoplasia, grade III (CIN III), and cervical cancer was examined among a cohort of 6,812 women in Tromsö, Norway, between 1980 and 1989. During the 52,844 person-years of observation, 185 incident cases (177 women with CIN III and eight with cervical cancer) were recorded in the regional pathology registry. The age-adjusted incidence rates of CIN III and cervical cancer were 267/100,000 person-years among women who had never smoked, 183/100,000 person-years among exsmokers, and 476/100,000 person-years among current smokers. A multivariate model containing terms for age, marital status, and frequency of intoxication yielded a relative rate for current smokers compared with nonsmokers of 1.5 (95% confidence interval 1.0-2.2). Statistical trend tests for the number of cigarettes smoked per day (never, 1-14, and greater than or equal to 15 cigarettes), years of smoking (never, 1-9, and greater than or equal to 10 years), and age started smoking (less than 16, 16-18, 19-21, and greater than or equal to 22 years) all yielded significant results. These findings support the opinion that CIN III and cervical cancer are a smoking-related disease.

Adult↗
PubMed1992

A follow-up study of agricultural chemical production workers.

This retrospective follow-up study evaluated the mortality experience of 4,323 men employed at a plant in Alabama (AL) that manufactures agricultural and other chemicals. On average, there were 18 years of follow-up per subject during the study period of 1951 to 1987. The observed numbers of deaths among cohort members were compared with the numbers expected on the basis of United States (US) and AL general population mortality rates. The all causes standardized mortality ratio (SMR), computed using US rates as the referent, was 97 (233 observed/240 expected deaths) for whites and 68 (47/69) for blacks. White subjects had more than expected deaths from buccal cavity and pharynx (BCP) cancer [SMR = 388; 95% confidence interval (CI) = 125-905] and from esophageal cancer (SMR = 417; 112-1,067). Their lung cancer mortality rate was 50% higher than the rate of US white men and 14% higher than the rate of AL white men. Each of these three cancers has strong nonoccupational determinants, the roles of which were not assessed and which may have been responsible in whole or in part for the observed increases. The excesses of lung and esophageal cancer were concentrated among short-term employees, an observation which also argues against a causal link with occupational factors. Black men experienced no increased mortality from BCP, esophageal or lung cancer, but results for blacks were imprecise. For white and black subjects combined, there were 3 observed versus 0.62 expected deaths due to soft tissue sarcoma (p = 0.05). The job histories of subjects with this type of cancer did not suggest any shared occupational exposure.

Black or African American↗
PubMed1992

A case-control study of lung cancer at a dye and resin manufacturing plant.

This case-control study evaluated the relationship between lung cancer and occupational factors among employees at a dye and resin manufacturing plant. The study included 51 lung cancer cases and 102 controls who were members of a cohort of workers investigated in a previous retrospective follow-up study. Information on area of employment and on potential exposure to certain chemicals was obtained from plant personnel and medical records and from interviews with long-term employees. Information on potential confounders, including cigarette smoking, was obtained by interviewing study subjects or their next-of-kin. The odds ratio (OR) for heavy smokers compared with light or nonsmokers was 5.9 (95% confidence interval (CI) = 2.4-15). An elevated OR for lung cancer was observed for subjects who worked in the anthraquinone dye and epichlorohydrin manufacturing area of the plant (OR = 2.4; 95% CI = 1.1-5.2) and for employees who were seen at the plant infirmary for acute exposure to chlorine (OR, adjusted for smoking = 27; 95% CI = 3.5-205). Pipefitters employed at the plant for five or more years also had an elevated OR (3.3; 95% CI = 0.8-14).

Adult↗
PubMed1991

Endometrial cancer, obesity, and body fat distribution.

A case-control study was undertaken to evaluate the roles of obesity and body fat distribution in the etiology of endometrial cancer. The study also included an evaluation of the associations of serum estrone, estradiol, and androstenedione with obesity, body fat distribution, and endometrial cancer risk. The study included 168 cases and 334 control subjects identified at an optometry clinic. A strong, positive relationship between overall obesity and endometrial cancer was found. The relative rate of endometrial cancer for women in the upper 90th percentile of a body mass index compared to those below the median was estimated as 5.5 with 95% confidence limits of 3.2-9.6. There was no association between endometrial cancer and the waist to hip ratio, an index of upper versus lower body fat distribution. A statistical test of trend across the four quartiles of the waist to hip ratio yielded a P value of 0.45 after adjustment for confounding by the body mass index. On the other hand, there was a statistically significant, independent positive effect of a high subscapular to tricep skinfold ratio, a measure of central versus peripheral obesity, on endometrial cancer risk. The relative rates of endometrial cancer for the second, third, or fourth quartile compared to the first quartile of this index were 1.5, 1.9, and 2.7, respectively (P = 0.007), after adjustment for the body mass index. Serum estrone and estradiol, but not androstenedione, were statistically significantly correlated with the body mass index among control subjects (r = 0.37 and 0.40 for estrone and estradiol, respectively). On the other hand, each of the sex hormones was uncorrelated with the waist to hip ratio after adjustment for body mass. The correlations between each of the three hormones and the subscapular to tricep skinfold ratio among controls were weak and were not statistically significant (0.10, 0.10, and 0.14 for estrone, estradiol and androstenedione, respectively). Cases had statistically significantly higher mean serum estrogen and androstenedione levels than did controls and these elevations did not simply reflect a higher prevalence of obesity among them. The findings are equivocal with respect to fat patterns and endometrial cancer. We suggest that future epidemiological studies of cancer and body fat distribution more carefully distinguish among the various types of fat patterns.

Adipose Tissue↗
PubMed1991

An efficient program for computing conditional maximum likelihood estimates and exact confidence limits for a common odds ratio.

This paper describes a method and associated computer program for calculating exact confidence limits and P values, along with the conditional maximum likelihood estimate of the common odds ratio for a series of 2 x 2 tables. The program can be used to calculate exact estimates for matched data and is considerably faster than others currently available.

Algorithms↗
PubMed1990

A follow-up study of methods of contraception, sexual activity, and rates of trichomoniasis, candidiasis, and bacterial vaginosis.

A randomized, clinical trial was conducted to evaluate the spermicidal agent nonoxynol 9 as prophylaxis for sexually transmitted diseases. Eight hundred eighteen women using birth control who attended a sexually transmitted disease clinic were evaluated monthly for trichomoniasis, candidiasis, and bacterial vaginosis for 6 months. Women using the active spermicide experienced a somewhat lower incidence rate of trichomoniasis (relative rate 0.83; 95% confidence interval 0.61 to 1.12) and bacterial vaginosis (relative rate 0.86; 95% confidence interval 0.69 to 1.12) as compared with placebo users. The rate of candidiasis was nearly identical for spermicide and placebo users (relative rate 1.02; 95% confidence interval 0.77 to 1.35). The number of sexual partners during the preceding month was related directly to the occurrence of trichomoniasis (p = 0.047) and bacterial vaginosis (p = 0.009) but not candidiasis (p = 0.99). Subjects using oral contraceptives experienced a statistically significant lower rate of trichomoniasis than did women using an intrauterine contraceptive device or who had had a tubal ligation (relative rate 0.56; 95% confidence interval 0.39 to 0.81).

Adult↗
PubMed1989

Oral contraceptive use and the risk of chlamydial and gonococcal infections.

Oral contraceptive users were compared with nonusers with respect to the rate of cervical infections by Chlamydia trachomatis and Neisseria gonorrhoeae. The comparison was adjusted for differences in demographic and behavioral characteristics between the two groups. The rates of infection among oral contraceptive users were increased by approximately 70% (statistically significant) for both pathogens. Cervical ectopy was implicated in the increased rate of chlamydia but not gonorrhea. Rates of gonorrheal infection differed significantly among oral contraceptive formulations; rates were higher for formulations containing more androgenic progestins.

Adult↗
PubMed1989

Bias arising in case-control studies from selection of controls from overlapping groups.

Three examples are used to demonstrate that the selection of controls from categories that overlap can lead to bias. Case-control studies that use friend controls and the practice of age-matching controls to cases within a specified number of years (caliper matching) are examples of the selection bias described in the paper. The bias resulting from the use of friend controls can be large and, since the use of friend controls is common, this source of bias is of considerable practical consequence. The use of friend controls or the selection of controls according to other variables with categories that overlap should be avoided.

Age Factors↗
PubMed1989

A prospective follow-up study of cancer mortality in relation to serum DDT.

Serum DDT and DDE levels were measured in 919 subjects in 1974 and 1975. Two-hundred and nine of the subjects died, including 54 from cancer, during a 10-year prospective follow-up period. There was no relation between either overall mortality or cancer mortality and increasing serum DDT levels. There was weak evidence of a positive relation between respiratory cancer mortality and serum DDT. The literature on DDT and human cancer is reviewed, and it is concluded that the evidence does not support the opinion that DDT is a human carcinogen.

Adult↗
PubMed1988

A clinical trial of nonoxynol-9 for preventing gonococcal and chlamydial infections.

A randomized, double-blind, placebo-controlled trial was conducted to evaluate the spermicidal agent nonoxynol-9 as prophylaxis for cervical infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae. Eight hundred eighteen women were recruited from a sexually transmitted disease clinic. Only subjects who were using reliable birth control methods (oral contraceptives, intrauterine device, or sterilization) were eligible. Subjects were randomly assigned to use either a commercially available spermicidal agent containing nonoxynol-9 or a placebo preparation. Subjects were followed up for six months; specimens were collected monthly for culture of the two pathogens. Women assigned to the nonoxynol-9 group were less likely to become infected with N. gonorrhoeae (relative rate, 0.75; 90% confidence limits, 0.58 and 0.96) and C. trachomatis (relative rate, 0.79; 90% confidence limits, 0.64 and 0.97). Among women who used their assigned gel for the majority of coital episodes, a stronger protective effect was observed.

Adult↗
PubMed1988

Benzene and leukemia. A review of the literature and a risk assessment.

Benzene is widely recognized as a leukemogen, and the Occupational Safety and Health Administration is currently attempting to limit exposure to it more strictly. The proposed new regulation is a limit of an eight-hour time-weighted average of 1 ppm in place of the current limit of 10 ppm. The fundamental rationale for the change is a perception that the current standard is associated with an inordinate excess of leukemia. The epidemiologic literature on benzene and leukemia supports the inference that benzene causes acute myelocytic leukemia. However, the available data are too sparse, or suffer other limitations, to substantiate the idea that this causal association applies at low levels (i.e., 1-10 ppm) of benzene. Nonetheless, under the assumption that causation does apply at such low levels, a number of authors, including ourselves, have performed risk assessments using similar data but different methodologies. The assessments that we consider acceptable suggest that, among 1,000 men exposed to benzene at 10 ppm for a working lifetime of 30 years, there would occur about 50 excess deaths due to leukemia in addition to the baseline expectation of seven deaths. However, this estimate is speculative and whether or not enough confidence can be placed in it to justify a lower occupational benzene standard remains a decision for policy makers.

Benzene↗
PubMed1987

Case-control study of hepatocellular carcinoma, occupation, and chemical exposures.

The relation of hepatocellular carcinoma (HCC) to occupation and chemical exposures was evaluated in a case-control study. The study included 80 cases and 146 matched hospital controls on whom a work history was obtained. No persuasively positive association between HCC and any particular occupation, industry, or chemical exposure was found. However, the relative rate (RR) of HCC for persons employed in highway construction compared with those never so employed is 5.0 with 95% confidence limits (CL), 1.0 to 26. The RR for farming occupations, 1.4 (95% CL, 0.7 to 2.9), is also slightly elevated. The RR for persons exposed to pesticides compared with those not exposed is 2.4 (95% CL, 0.9 to 6.5). Asphalt exposures are associated with a RR of 3.2 (95% CL, 0.9, 11). These findings are compared to the results of other epidemiologic studies.

Adult↗
PubMed1986

A case-control study of hepatocellular carcinoma and the hepatitis B virus, cigarette smoking, and alcohol consumption.

A case-control study was undertaken to evaluate the roles of the hepatitis B virus (HBV), cigarette smoking, and alcohol use in the etiology of hepatocellular carcinoma (HCC). A major purpose of the study was to evaluate the effect of cigarette smoking on HCC among hepatitis B surface antigen (HBsAg)-negative persons, since it had been suggested that the relative effect of cigarette smoking on HCC was higher among HBsAg-negative persons than among HBsAg-positive persons. Eighty-six cases and 161 hospital controls were included in the study. This study confirmed the strong relationship between the HBV and HCC. Twelve of 67 cases and none of 63 controls were chronically infected with HBV as evidenced by serum HBsAg. The study also found a moderately strong relationship between alcohol use and HCC. The results of the present study do not support the hypothesis that cigarette smoking is a risk factor for HCC. Among all subjects, the relative rate of HCC for cigarette smokers compared with nonsmokers after adjustment for alcohol consumption was 1.0 with 95% confidence limits, 0.5 to 1.8. Among HBsAg-negative subjects, the relative rate was 1.1 with 95% confidence limits, 0.5 to 2.4. There was also no consistent dose-response relationship between quantity smoked and HCC in this study.

Adult↗
PubMed1986

A case-control study of leukemia at an oil refinery.

A previous retrospective follow-up mortality study of white men employed at an oil refinery found an excess of leukemia deaths, especially of acute myeloid leukemia (AML). A case-control study was done to determine if the excess could be related to any particular jobs or departments at the refinery or to benzene exposures. The study includes 14 cases with leukemia (eight cases with AML) and 50 matched controls. No particular job or department was identified as the likely source of the excess leukemia deaths. Furthermore, the cases apparently had not been exposed to more benzene than had the controls. Thus, the reason for the excess leukemia at this refinery was not identified. The limitations of the study are discussed.

Benzene↗
PubMed1979

Breast cancer in black American women.

A case-control study of breast cancer among Black American women was conducted in seven hospitals in New York City from 1969 to 1975. Results are reported for 127 cases and 317 controls. Compared to women with a first birth before age 19, those with a first birth after 25 had a relative incidence rate for breast cancer of 3.8 and 2.2 for the pre- and postmenopausal age-groups, respectively. Compared to nulliparous women, parous women had a relative incidence rate of 0.6 for premenopausal and 0.7 for postmenopausal women. The incidence rate of breast cancer for women with a menopause after age 49 was estimated to be 3.1 times that of women with a menopause before age 45. Thus, the known risk factors for breast cancer among Whites are also related to the etiology of the disease among Blacks. The incidence rate of breast cancer has increased among younger Blacks since 1947 and is now similar to that among younger Whites. However, among older women, the incidence rate is still appreciably higher for Whites. The most likely explanation of this pattern is that Black women born since about 1925 are being exposed at the same frequency as White women to the causes of breast cancer.

Adolescent↗