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Biomedical subjects

B MacMahon

Publications and source records attributed to B MacMahon.

At least 73 records · Page 4Linked to original sources
PubMed1981

Coffee and cancer of the pancreas.

We questioned 369 patients with histologically proved cancer of the pancreas and 644 control patients about their use of tobacco, alcohol, tea, and coffee. There was a weak positive association between pancreatic cancer and cigarette smoking, but we found no association with use of cigars, pipe tobacco, alcoholic beverages, or tea. A strong association between coffee consumption and pancreatic cancer was evident in both sexes. The association was not affected by controlling for cigarette use. For the sexes combined, there was a significant dose-response relation (P approximately 0.001); after adjustment for cigarette smoking, the relative risk associated with drinking up to two cups of coffee per day was 1.8 (95% confidence limits, 1.0 to 3.0), and that with three or more cups per day was 2.7 (1.6 to 4.7). This association should be evaluated with other data; if it reflects a causal relation between coffee drinking and pancreatic cancer, coffee use might account for a substantial proportion of the cases of this disease in the United States.

Aged↗
PubMed1981

Lung cancer and passive smoking.

Fifty-one women with lung cancer and 163 other hospital patients were interviewed regarding the smoking habits of themselves and their husbands. Forty of the lung cancer cases and 149 of the other patients were non-smokers. Among the non-smoking women there was a statistically significant difference between the cancer cases and the other patients with respect to their husbands' smoking habits. Estimates of the relative risk of lung cancer associated with having a husband who smokes were 2.4 for a smoker of less than one pack and 3.4 for women whose husbands smoked more than one pack of cigarettes per day. The limitations of the data are examined; it is evident that further investigation of this issue is warranted.

Aged↗
PubMed1981

Elevated urine estrogen and pregnanediol levels in daughters of breast cancer patients.

Urine levels of three major estrogens and of pregnanediol were measured for 76 nulliparous daughters of breast cancer patients and for 115 control women of similar age and parity. Concentrations of estrone and estradiol tended to be higher in the daughters of breast cancer patients than in the controls; total estrogens were elevated in both phases than in the controls; total estrogens were elevated in both phases of the menstrual cycle and significantly so in the luteal phase. There was little difference between the daughters and the controls in estriol ratios--the ratios of the concentration of estriol to the sum of the concentrations of estrone and estradiol. Pregnanediol levels were higher in the daughters than in the controls.

Adolescent↗
PubMed1980

Pregnancy, delivery, and neonatal complications among autistic children.

An investigation of the prenatal, delivery, and neonatal experience of 145 autistic children matched with 330 unaffected siblings revealed that among the propositi there was a preponderance of first-born children. Obstetrical records, which had been made prior to the diagnosis of autism, indicated that autistic children were more likely than their siblings to have experienced at least one untoward event during their mothers' gestations and deliveries. Similarly, the autistic children had an increased risk of neonatal complications. Despite the significant excess of total reproductive complications in the autistic series, there was no single event or a combination of biologically related complications that could reasonably account for any large number of cases of autism. While it is possible that autism may be the product of several diverse deleterious events experienced in utero, during delivery, or in the early neonatal period, our finding could be a chance occurrence or could signal the presence of a unknown factor responsible both for autism and for a variety of reproductive complications.

Autistic Disorder↗
PubMed1980

Maternal age and birth rank of women with breast cancer.

Data from a large international case-control study of breast cancer suggested that women born to young mothers had a 25% lower risk of breast cancer. The association was not secondary to a tendency for these women themselves to have had children at early ages. The data provided no indication of a meaningful association between breast cancer risk and birth rank. Confounding was controlled by stratification according to a summary confounder score.

Adult↗
PubMed1980

Smoking and hepatitis B-negative primary hepatocellular carcinoma.

Smoking histories were obtained from 79 patients with primary hepatocellular carcinoma (PHC) (of whom 40 were negative and 39 positive for serum hepatitis B surface antigen), 39 patients with liver cancer not primary in the liver (LCNP), and 204 hospitalized controls. All subjects were Caucasians of Greek nationality and residence. No significant difference in smoking habits was found between controls and either PHC patients positive for serum hepatitis B surface antigen or LCNP patients. In contrast, there was a highly significant association between smoking and PHC negative for serum hepatitis B surface antigen (P less than 10(-4)); this association was not accounted for by the greater alcohol consumption of smokers. The risk ratios were 1.3, 2.5, 3.7, and 8.4 for current smokers of 1-10, 11-20, 21-30, and 30+ cigarettes per day.

Alcohol Drinking↗
PubMed1980

Socioeconomic status, urine estrogens, and breast cancer risk.

Urine estrogens were measured in 46 women students, ages 15-18, at a middle-class high school in Athens and in 40 women of the same age residing at one of three orphanages in the same city. The lower socioeconomic status (SES) of the latter group was documented by their lower mean height (by 5.2 cm) and weight (by 5.3 kg) relative to the high school students. Both in follicular and luteal phases of the menstrual cycle, the women with lower SES had 50% higher estriol ratios (ratio of the concentration of estriol to the sum of the concentrations of estrone and estradiol). In luteal specimens the concentration of all three major estrogens was higher in the group with low SES than in the women in the other group, but the concentration of estriol was most increased. There was also an indication of less frequent anovular cycles among the women with low SES. These findings are consistent with hypotheses linking either the estriol ratio or the frequency of anovular cycles to breast cancer risk.

Adolescent↗
PubMed1980

Estrogen profiles of primiparous and nulliparous women in Athens, Greece.

Urine estrogens of 144 primiparous women and 122 nulliparous women of similar age were measured. The primiparae were at least 6 months post pregnancy. The ratio of the estriol concentration to the sum of the concentrations of estrone and estradiol (the estriol ratio) was higher among primiparous women under 25 years of age than among nulliparous women of the same age. The difference was greater in specimens collected in the luteal phase of the menstrual cycle than in those collected in the follicular phase and was statistically significant (P less than 0.05, one-tailed t-test) only in the luteal phase. The high estriol ratios of the primiparous women did not decline with increasing interval after pregnancy, at least up to 24 months. Among the younger women, significantly lower levels of pregnanediol, suggestive of a higher frequency of anovular menstrual cycles, were also seen in the nulliparous women. The findings were consistent with the hypothesis that the protective effect against breast cancer of a full-term pregnancy at an early age operates either through a change in the pattern of estrogen metabolism induced by the pregnancy or through a change in the frequency of ovular cycles.

Adolescent↗
PubMed1979

Mortality of pesticide applicators.

Information has been obtained on a cohort of professional pesticide applicators which will be followed prospectively. The cohort consists of 16,126 males employed for three months or more between 1967 and 1976 by any of three nationwide pest control companies. Deaths which occurred between 1967 and 1976 were reported by the Social Security Administration as a result of a search of its records. Overall, 311 deaths were ascertained, giving a standardized mortality ration (SMR) of 84. SMRs were over 100 for three causes of death--cancer of the lung (115), cancer of the skin (173) and cancer of the bladder (277). The confidence intervals of two of these ratios include 100, and the observed numbers therefore do not differ significantly from those expected. For bladder cancer the excess is on the border of statistical significance (p less than 0.05). The excess of deaths from lung cancer was not seen for applicators classified as termite control operators, a group more likely to be exposed to chlordane and heptachlor. There were significantly low SMRs for cancer of the digestive organs (46) and for other diseases of the digestive (55) and respiratory (29) systems. Deaths from cerebrovascular disease were also less than expected, though not significantly so.

Cerebrovascular Disorders↗
PubMed1979

Mortality of workers employed in the manufacture of chlordane and heptachlor.

A retrospective mortality study has been carried out on workers employed in the manufacture of chlordane and heptachlor between 1946 and 1976. The study group was comprised of 1403 white males who worked for more than three months at either of the two plants in the United States now producing these compounds. Information on deaths among terminated employees was obtained from the Social Security Administration and supplemented by information collected by another investigator by individual follow-up. There were 113 deaths observed in the group, compared to 157 expected, giving a standardized mortality ratio (SMR) of 72. There was no overall excess of deaths from cancer, even among workers followed twenty or more years after entry into the occupation. There was one death from liver cancer. An excess of deaths from lung cancer (12 observed, 9.0 expected) was not statistically significant and was not distributed by duration of exposure or of latency in any pattern suggesting an etiologic role for chlordane-heptachlor exposure. Although diseases of the circulatory system as a whole showed fewer deaths than expected (SMR 83), there was a statistically significant excess of deaths from cerebrovascular disease (17 observed, 9.3 expected). This excess was not related to duration of exposure or latency and occurred exclusively after termination of employment.

Chemical Industry↗
PubMed1979

The incidence of seizures among children with autistic symptoms.

The authors examined 183 children with autistic symptoms and found that the age-specific incidence rates of seizures in this sample were between 3 and 28 times the rates for children in the general population. The subjects classified as totally autistic were at high risk of developing seizure from early childhood well into adolescence, but especially so at puberty. The partially autistic children had an increased risk of seizures only up to age 10. The authors suggest that the high incidence of seizures at puberty observed in this study may be specific to children with total autistic symptomatology and may represent a distinct pathological process associated with autism.

Adolescent↗