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Biomedical subjects

C G Humble

Publications and source records attributed to C G Humble.

At least 19 recordsLinked to original sources

Cigarette smoking and lung cancer in New Mexico.

We have used population-based data for the state of New Mexico to calculate cigarette-smoking-specific incidence rates for lung cancer, cumulative incidence rates for lung cancer, and estimates of the proportion of lung cancer cases attributable to smoking. For white New Mexicans, the incidence of lung cancer increased with age and was markedly higher in smokers than in nonsmokers. From 25 through 84 yr of age, the cumulative incidence of lung cancer was 0.9% in nonsmoking males and 0.5% in nonsmoking females. The cumulative incidence rates were much higher for smokers; for males who smoked 20 or more cigarettes daily from age 25, the cumulative risk of lung cancer through age 84 was 31.7%. For females with the same cigarette smoking history, the estimate of cumulative incidence through age 84 years was 15.3%. The population-attributable risks for lung cancer associated with cigarette smoking were 89.5% for males and 85.5% for females.

Adult↗

Cancer treatment protocols. Who gets chosen?

We compared the age distribution of all adults in New Mexico with cancer incident from 1959 through 1982 with that of all adult New Mexican patients enrolled in cancer treatment protocols sponsored by the Southwest Oncology Group (New Mexico). For all cancer sites, elderly patients were substantially underrepresented in the Southwest Oncology Group protocols. While 31% of all adult patients with cancer were over age 70 years, only 7% of patients with cancer enrolled in Southwest Oncology Group protocols were in that age group. The underrepresentation of elderly individuals in cancer treatment protocols will make it difficult to determine optimal therapies for older patients with cancer.

Age Factors↗

Factors influencing discrepancies between premortem and postmortem diagnoses.

A study of 2067 autopsies collected from 32 university and community hospitals of various sizes located throughout the United States showed the rate of discrepancies between premortem and postmortem diagnoses to be influenced by the type and size of hospital, the age and sex of the patient, and the disease responsible for the patient's death. Of equivocal or no influence were the length of the terminal hospitalization, the degree of clinical involvement in the case of the person responsible for establishing the discrepancy level, and the autopsy rate, at least as it applies to community hospitals.

Adolescent↗

Use of quantified and frequency indices of vitamin A intake in a case-control study of lung cancer.

Recent publications have examined the extent of food frequency data needed to estimate nutrient intakes in epidemiological studies. The need for amount (usual portion size) data to supplement information on average frequency of intake has been questioned. In a case-control study of risk factors for lung cancer, we have collected data on frequency, amount and past pattern of intake for common or rich sources of vitamin A. These data have been combined with standard content information to calculate three different types of indices: one based on frequency alone, a quantitative index that included both frequency and amount, and a past-weighted index that combined the frequency, amount and data on relative consumption in the past. Odds ratios by tercile of carotene, retinol and total vitamin A intake varied little between the frequency index and the quantified and past-weighted indices. Higher intakes of carotene and total vitamin A were associated with a lower risk for lung cancer regardless of index type. This consistency of results is explained by a stability of relative intakes regardless of index type. Spearman rank order correlation coefficients between the frequency and quantitative indices exceeded 0.90 for total vitamin A, carotene, and retinol. This stability is attributable to parallel trends of increased frequency of consumption and portion size at higher levels of nutrient intake. Because similar trends were observed in five main food groups included in these analyses, these findings may be generalizable to other nutrients.

Aged↗

Histopathology of lung cancer in New Mexico, 1970-72 and 1980-81.

In conjunction with a population-based case-control study of lung cancer in New Mexico, the histopathology of cases diagnosed during 1980 and 1981 and during 1970-72 was reviewed. Adequate histologic or cytologic material was obtained for 725 cases, with 308 during 1970-72 and 417 during 1980-81. The light microscopic histologic type was classified on the basis of review by 2 pathologists. No significant differences were found in the histologic-type distributions in Hispanics and non-Hispanic whites. In males, the distributions of histologic types were similar in the two time periods, but in non-Hispanic white women the proportion of adenocarcinoma declined during 1980-81 as the proportion of small cell carcinoma increased. The panel classification was compared with that recorded by the New Mexico Tumor Registry. Overall agreement was 52.1% for 1970-72 and increased to 65.2% for 1980-81. The discrepancies between the two classifications were largest for the categories of large cell undifferentiated carcinoma and "other malignancy."

Adenocarcinoma↗

History of residence and lung cancer risk in New Mexico.

Participants in a population-based case-control study of lung cancer in New Mexico between 1980 and 1982 were asked to identify all locations where they had resided for six months or more. These residential data were coded at the county and state levels and combined with county-level socioeconomic data from the 1910, 1930, 1950, and 1970 decennial censuses to generate indices of time lived in counties or metropolitan areas of different sizes, degrees of urbanization, or extents of employment in manufacturing industries. Urban residence was not associated with employment of male controls in jobs or industries considered to increase lung cancer risk. However, in the non-Hispanic white female controls, urban residence before age 30 years in a county of 500,000 or more residents was associated with a fourfold higher odds ratio for starting to smoke cigarettes. Male and female non-Hispanic controls who had ever lived in more populous counties smoked more cigarettes per day than did those who had not lived in such counties. Residential history patterns were the same in cases and controls; multiple logistic regression showed no consistent associations of the residence history variables with lung cancer risk.

Adult↗

Marriage to a smoker and lung cancer risk.

As part of a population-based case-control study of lung cancer in New Mexico, we have collected data on spouses' tobacco smoking habits and on-the-job exposure to asbestos. The present analyses include 609 cases and 781 controls with known passive and personal smoking status, of whom 28 were lifelong nonsmokers with lung cancer. While no effect of spouse cigarette smoking was found among current or former smokers, never smokers married to smokers had about a two-fold increased risk of lung cancer. Lung cancer risk in never smokers also increased with duration of exposure to a smoking spouse, but not with increasing number of cigarettes smoked per day by the spouse. Our findings are consistent with previous reports of elevated risk for lung cancer among never smokers living with a spouse who smokes cigarettes.

Aged↗

Choice of cancer therapy varies with age of patient.

We used data on 22,899 cancer cases collected by the New Mexico Tumor Registry to examine the relationship between patient age and the use of potentially curative therapy for cancers of selected sites and acute leukemias. For cancers of most sites, either local or regional stage, the proportion of cases receiving potentially curative therapy declined with age. For local-stage cancers, the proportion not given any treatment increased with age. Overall mortality rates during the first year after diagnosis were much higher for local-stage cases without treatment than for those who received treatment. These data show that cancer therapy varies with age and suggest that decision making regarding therapy is influenced by the presence of other diseases.

Adult↗

Determinants of lung cancer risk in cigarette smokers in New Mexico.

Although cigarette smoking is the strongest known risk factor for lung cancer, the effects of specific smoking practices have not been completely characterized. The present study examines determinants of lung cancer risk in a population-based, case-control study conducted in New Mexico, 1980-82. The study included 521 cases and 769 controls matched for age, sex, and ethnicity. Either the index subjects or their next-of-kin were interviewed in person to obtain a detailed history of cigarette smoking and information concerning other risk factors. With the use of multiple logistic regression, a model was constructed of the effects of amount smoked, duration of smoking, cigarette type, and smoking cessation on lung cancer risk. Among current smokers, risk increased with each additional cigarette smoked per day (P less than .001). For duration of smoking, the risk per year smoked in individuals 65 years and older was only one-third that in persons under age 65 years. With regard to cigarette type, a somewhat higher risk was found associated with smoking nonfilter cigarettes, but there was no evidence of decreasing risk as the extent of filter smoking increased. Lifelong filter cigarette smokers and smokers of both filter and nonfilter cigarettes were at lower risk than lifelong smokers of nonfilter cigarettes only. In ex-smokers, the pattern of variation of relative risk with amount and duration was similar to that in the current smokers. Excluding those who had stopped for 1 year or less, the relative risk declined exponentially with duration of smoking cessation (P less than .01). These analyses confirm the strong benefits of smoking cessation and indicate possible reduction of risk from smoking filter cigarettes.

Adult↗

Personal and family history of respiratory disease and lung cancer risk.

Lung cancer risk associated with family and personal history of respiratory diseases was assessed in a population-based, case-control study that included incident cases in New Mexico, 1980 to 1982. The study questionnaire ascertained previous diagnoses of major chronic respiratory diseases in the index subjects, their parents, and their grandparents and of lung and other respiratory cancers in the parents and grandparents. Physician diagnoses of chronic bronchitis, emphysema, asthma, and other chest illnesses were reported significantly more often for cases than for control subjects. For 6.9% of the cases, at least 1 parent had a diagnosis of lung cancer, whereas only 2.2% of the control subjects' parents were similarly affected (p less than 0.001). In multiple logistic regression models that excluded never smokers and included variables to control for the effects of cigarette smoking, we found significantly increased risks for a personal history of chronic bronchitis or emphysema (odds ratio = 2.0; 95% confidence interval, 1.4 to 2.8) and a parental history of lung cancer (odds ratio = 5.3; 95% confidence interval, 2.2 to 12.8). The present study complements the results of previous investigations, which demonstrated that lung cancer risk in smokers is modified by characteristics of the smoker and by family history.

Aged↗

Lung cancer risk and vitamin A consumption in New Mexico.

The association between dietary intake of vitamin A and lung cancer risk was examined in a population-based, case-control study of 447 patients and 759 control subjects in New Mexico. A food frequency interview was used to measure usual consumption of total vitamin A retinol, preformed vitamin A, and carotene. With all respondents combined, the odds ratios for lung cancer increased as intakes of total vitamin A and carotene declined but did not vary with intake of preformed vitamin A. When the subjects were stratified by ethnic group, Hispanic or non-Hispanic (Anglo) white, significant effects of vitamin A consumption were limited to the Anglos. In the Anglos, the protective effects of total vitamin A and carotene consumption were present in males and females, but varied strongly with cigarette smoking habits. In Anglo smokers, significant increases in the odds ratios with declining intake were observed in former but not in current smokers. Among the former smokers, significant effects of total vitamin A and carotene consumption were present only in those who had stopped smoking for 6 to 15 yr. Limitation of the protective effect of vitamin A and carotene consumption to past smokers has important implications for the design of clinical trials and for cancer control strategies.

Aged↗

Cigarette smoking and lung cancer in 'Hispanic' whites and other whites in New Mexico.

A population-based case-control study of lung cancer was performed in New Mexico to explain the differing patterns of lung cancer occurrence in the state's "Hispanic" Whites and other Whites. From 1980 through 1982, interviews were completed with 521 cases and 769 controls. In the male controls, the prevalence of current and previous cigarette usage was similar in the two ethnic groups, but Hispanics smoked fewer cigarettes daily. In the female controls, a lower percentage of Hispanics had ever smoked and their usual consumption was less than that of other White women. Older Hispanic female smokers had used hand-rolled cigarettes for an average of 8.8 years, whereas other White women of the same age had used this type for less than one-half year. Both stratified and multiple logistic analysis showed comparable risks of lung cancer in Hispanic White and other White smokers. There was no evidence of interaction between ethnicity and cigarette smoking. These analyses imply that the differences in lung cancer incidence between New Mexico's Hispanic Whites and other Whites are largely explained by the patterns of cigarette smoking of these two groups.

Adult↗

Comparison of self- and surrogate-reported dietary information.

Studies of diet's role in the etiology of rapidly fatal diseases may utilize data taken from surrogate sources. To assess such sources, 46 subject-spouse pairs were interviewed with a food frequency questionnaire designed to provide an index of vitamin A consumption. Information concerning amount and past pattern of use was also obtained. The frequency and amount information was used to calculate two aggregate indices of vitamin A consumption: one based on frequency alone and the other based on frequency and amount. For single foods, the mean frequencies of consumption reported by subjects and by their spouses for them were similar; for both sexes combined, the average level of exact agreement was 66 per cent, with improvement to 93 per cent for agreement within one category. Similar agreement was found for amount. For the overall daily vitamin A intake of men, the means based on subject data were not significantly different from those calculated from their wives' responses. For women, husbands underreported their total intake. Agreement between subject- and surrogate-based overall vitamin A consumption was less satisfactory than for the individual foods.

Adult↗

Alternatives in the collection and analysis of food frequency interview data.

In addition to frequency of consumption, a food frequency questionnaire may assess amount consumed, often by using food models, and the stability of diet. A food frequency interview directed at preformed vitamin A and beta-carotene was administered to 130 cases and 309 controls in an ongoing population-based case-control study of lung cancer in New Mexico. The questionnaire measured frequency, amount, and stability of consumption for 55 food items. Different combinations of responses to these three types of questions were used to calculate indices of total vitamin A consumption. The index based on frequency alone had the lowest value and increased significantly when amount was combined with frequency. Consideration of past consumption had relatively little effect on absolute and relative estimates of intake. Spearman rank order correlations between index pairs were high. These results suggest that the use of frequency alone is appropriate when the objective of data collection is to establish subjects' relative intake of specific nutrients.

Adult↗

Prevalence survey of respiratory abnormalities in New Mexico uranium miners.

To obtain additional data concerning uranium mining and nonmalignant respiratory diseases, we conducted a prevalence survey of 192 long-term New Mexico uranium miners. Survey procedures included spirometry, completion of a respiratory symptoms questionnaire, physical examination and interpretation of available chest x rays. Total duration of underground uranium mining was used as the exposure index. Of the major respiratory symptoms, only the prevalence of dyspnea increased significantly with duration of uranium mining. With linear multiple-regression analysis, small but statistically significant effects of mining were found for two spirometric parameters, the forced expiratory volume in one sec and the maximal midexpiratory flow. By the 1980 International Labor Organization (ILO) U/C classification, 12 of 143 participants with x rays available for interpretation had at least category 1/0 pneumoconiosis. The opacities were predominantly nodular and compatible with silicosis.

Adult↗

Polybrominated biphenyls and fetal mortality in Michigan.

The contamination of the Michigan food supply by polybrominated biphenyls (PBBs) in the mid-1970s appears to have had little or no impact on fetal mortality. Comparison of fetal death rates among residents of Lower Peninsula counties with a high percentage of quarantined farms and among residents of Upper Peninsula counties with no quarantined farms reveals no important differences in rates or trends after the contamination. Since counts of early spontaneous abortions are lacking, a complete assessment of the possible impact on reproductive outcome cannot be made.

Abortion, Spontaneous↗