ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

This study examined the association of physical exertion and spontaneous abortion in a case-control study of 607 women whose pregnancies ended in spontaneous abortion and 1,287 women who delivered livebirths in Santa Clara County, CA, in 1986 and 1987. We interviewed women about the number of hours they spent doing heavy housework and caring for young children. We also interviewed women employed during their pregnancies (71% in each group) about their work schedule; the number of hours they worked, stood, commuted, and stooped or bent; and the number of times per day they lifted weights of >15 pounds. Standing >8 hours per day at work was the only variable associated with increased risk [adjusted odds ratio (OR) = 1.6; 95% confidence limits (CL) = 1.1, 2.3]. This association was present only for women with a history of spontaneous abortion (adjusted OR = 2.8; 95% CL = 1.4, 5.9). Among women with this history, the OR for a second trimester abortion was 4.9 (95% CL = 1.9, 12.2). Cleaning house for >7 hours per week or caring for young children for >50 hours per week was associated with decreased risk (adjusted OR = 0.6, 95% CL = 0.5, 0.9; adjusted OR = 0.8, 95% CL = 0.6, 1.0, respectively). Again, these associations were specific to women with a history of spontaneous abortion (adjusted OR = 0.4, 95% CL = 0.2, 0.7; adjusted OR = 0.5, 95% CL = 0.3, 0.8). These results indicate that the specific type of physical exertion, the amount of exertion, and the context of the exertion may be important.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We examined the influence of the level of occupational physical activity per working hour (intensity score) and per working day (fatigue score) on menstrual function and fecundability in a population of 260 nonmedical female workers who were employed at 39 Dutch hospitals and were planning a pregnancy. We studied the influence of the intensity and fatigue scores as such and in combination with unfavorable working hours (before 8:00 am or after 6:00 pm) and high working speed (working at high speed for more than 50% of the time). The data did not reveal a clear relation between the occupational physical activity levels (representing an estimated energy requirement of up to 3 times the basal metabolic rate) and menstrual function, but the presence of a small effect could have been missed. The fecundability of women with a high fatigue score, particularly in association with unfavorable working hours, was lower than that of women with a low fatigue score (fecundability odds ratio = 0.37; 95% confidence interval = 0.18–0.77). Moderate levels of physical activity, as found in cleaners, kitchen staff, and clerical workers at hospitals, appear to affect the female reproductive system. Fecundability, as measured by the time to pregnancy, seems to be a more sensitive parameter for these biological changes than menstrual function.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

We examined the association between plasma lipids and total ascorbic acid in 256 men and 221 women age 20–65 years. Among men, we observed that high-density lipoprotein (HDL) cholesterol was 2.1 mg per dl higher, total:HDL cholesterol was 5.4% lower, total cholesterol was 4.8 mg per dl lower, low-density lipoprotein (LDL) cholesterol was 5.6 mg per dl lower, and triglyceride was 5.2% lower for each 0.5 mg per dl increment in ascorbic acid. The association between ascorbic acid and total:HDL cholesterol ratio in men was modified by glucose concentration. Among women, we observed that HDL cholesterol was 14.9 mg per dl higher for women with ascorbic acid levels ≤1.05 mg per dl and 0.9 mg per dl lower for women with ascorbic acid levels >1.05mg per dl for each 0.5 mg per dl increment in ascorbic acid. Total:HDL cholesterol ratio was 10.9% lower for women with ascorbic acid concentrations ≤1.45 mg per dl and 0.6% higher for women with ascorbic acid concentrations >1.45 mg per dl for each 0.5 mg per dl increment. The associations among ascorbic acid concentration, total and LDL cholesterol, and triglyceride concentrations were weak or absent among women. These results are consistent with earlier observations relating ascorbic acid and HDL cholesterol and indicate that ascorbic acid might also be related to total and LDL cholesterol concentrations in men.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Cumulative damage models are a macroscopic approach to describe the epidemiologic aspects of carcinogenesis. This approach is based on the conjectures that cancer epidemiology (a) may derive only limited insight into specific biologic processes, and (b) may need no detailed biologic assumptions to obtain sufficient understanding of the relation between environmental exposures and host responses in human populations. The cumulative damage model leads intrinsically to the theoretical interpretation of the epidemiologic aspects of carcinogenesis as a kind of wear-out process. In the present paper, it has been applied to the data of the British physicians' study and is contrasted with some other convenient models. The comparisons show that all considered models fit the data reasonably well. The conclusion is essentially theoretical: because the present model fits the data sufficiently closely, but is based on rather parsimonious biologic assumptions, the specific referral of epidemiologic observations to cellular events, as done by other approaches, might be an overinter-pretation of the data.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

I developed a 5-stage, 7-compartment prognostic model for the long-term follow-up of 28 patients with sickle chronic lung disease. Estimated hazard functions for transition varied with Stage 1, 2, 3, or 4 of sickle chronic lung disease as well as with stage at diagnosis and duration of observation with hematologic disease before the recognition of sickle chronic lung disease. Individualized hazard matrices produced 28 prognostic probability functions of time that had heterogeneous levels and shapes. The probability of death from the time of diagnosis to the end of each patient's period of follow-up determined that patient's prognostic integrated hazard. Such integrated hazard values, developed from a prognostic model, provide a superior context for carrying out standard formal tests and inferences regarding the effects of alternative treatments in randomized clinical trials.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Blacks appear to have a lower risk of fractures than whites, but there has been little research regarding racial differences in the risk of fractures at sites other than the hip. We used Medicare claims to investigate the risks of fractures of the hip, distal forearm, proximal humerus, and ankle among American whites and blacks over 65 years old. Each of these fractures occurred more frequently in women than in men and (except for ankle fracture) displayed an increase in risk with age. Blacks had a lower risk than whites, although these differences were smaller for fractures of the ankle and were less pronounced among men. The most likely explanation for this is a constitutional or metabolic factor prevalent in blacks that particularly influences the risk of osteoporotic fractures in women.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Based on the Atomic Bomb Casualty Commission/Radiation Effects Research Foundation series of over 5,000 autopsies, we examined death certificate accuracy for 12 disease categories and assessed the effect of potential modifying factors on agreement and accuracy. The overall percentage agreement between death certificate and autopsy diagnoses was only 52.5%. Although neoplasms had the highest detection rate, almost 25% of cancers diagnosed at autopsy were nevertheless missed on death certificates. Confirmation and detection rates were above 70% for neoplasms and external causes of death only. Confirmation rates were between 50 and 70% for infectious diseases and heart and other vascular diseases. Detection rates reached a similar level for infectious, cere- brovascular, and digestive diseases. Specificity rates were above 90% for all except the cerebrovascular disease category.Overall agreement decreased with increasing age at death and was worse for deaths occurring outside of hospital. There was some suggestion that agreement improved over time, but no indication that radiation dose, sex, city of residence, or inclusion in a biennial clinical examination program influenced agreement. Since the inaccuracy of death certificate diagnoses can have major implications for health research and planning, it is important to be aware that their accuracy is low and that it can vary widely depending on cause, age, and place of death.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

It has been suggested that the well known associations between smoking and cancer may in part reflect inadequately controlled confounding due to occupational exposures. The purpose of the present analysis is to describe the association between cigarette smoking and both lung and bladder cancers, taking into account the potential confounding effects of over 300 covariates, most of which represent occupational exposures. A population-based case-control study was undertaken in Montreal to investigate the associations between a large variety of environmental and occupational exposures, on the one hand, and several types of cancer, on the other. Interviews were carried out with male incident cases of several sites of cancer, including 857 lung cancers and 484 bladder cancers. A group of non-smoking-related cancers, comprising 1,707 interviewed subjects, was used as one control group. Additionally, 533 population controls were interviewed and constituted a second control group. Interview information included detailed lifetime smoking histories, job histories, and other potential confounders. Each job history was reviewed by a team of experts who translated it into a history of occupational exposures. These occupational exposures, as well as nonoccupational covariates, were treated as potential confounders in the analysis of cigarette smoking effects. Regardless of whether population controls or cancer controls were used, the odds ratio (OR) between smoking and lung cancer (ranging from 12 to 16 for ever vs never smokers) was not materially affected by adjustment for occupational exposures. The odds ratios for bladder cancer (ranging from 2 to 3) were also unaffected by confounding due to occupational exposures. Because of the extensive information available on occupational exposures, it is possible to affirm that the reported associations between smoking and both lung and bladder cancer do not result from inadequate control for occupational confounders. The consistency of findings when using two different control groups further diminishes the possibility that the results represent an artifact of inadequate research design.

ISSN:1044-3983    

出版商:OVID    

年代:1994

数据来源: OVID