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PubMed2006

Assessment of sublethal effects of clofentezine on life-table parameters in Hawthorn spider mite (Tetranychus viennensis).

A leaf disc bioassay was employed in the laboratory to assess the population responses of Tetranychus viennensis Zacher to clofentezine at three concentrations (LC(10), LC(25) and LC(50)) in three successive generations. Life-table parameters were calculated in each acaricide exposure regime and compared by jackknife procedures. Clofentezine treatments in the juvenile stages significantly delayed development of the mites, and this delay increased with increasing dose but decreased as the mites developed. Exposure to clofentezine reduced the net reproduction rate (R(0)) in a concentration-dependent manner. The LC(50) treatment had strong effects on the hatchability of eggs produced by surviving females. Hatch rate dropped from 0.83 in the untreated control to 0.51 in the third generation. When exposed to constant concentrations of clofentezine in three successive generations, the intrinsic rate of increase and R(0) of the mites decreased significantly, but they increased significantly when exposed to decreasing concentrations. Unexposed offspring of the exposed mother also displayed increases in R(0) and the jackknife procedures indicated no significant differences in R(0) between LC(10) and LC(25) offspring and their mothers vs. the control, while R(0) in unexposed LC(50) offspring was significantly higher than their mother's, but lower than that in the control. These changing patterns of r(m) reveal that acaricide effects at the population level strongly depend on the life-history characteristics of T. viennensis and the chemical mode of action.

Aging↗
PubMed1984

Limited life-table factors for estimating radiation-induced cancers over finite time periods.

A method is presented that allows the estimation of radiation-induced cancer incidence or mortality at varying times post-exposure in irradiated populations of males or females of ages ranging from 10 to 70 yr. Limited life-table factors are given in graphic form for 2 sets of conditions: when the latent period is 2 yr and the plateau 30 yr and when the latent period is 10 yr and the plateau extends to the end of life. Normal incidences for selected forms of cancer are also presented. Examples are given that show how to calculate the radiation excess cancers and to compare this excess with the normal. The implications of these numbers are also discussed.

Actuarial Analysis↗
PubMed1984

Prediction of time to delivery from start of contractions in induced labor: a life table analysis approach.

Labor was induced in a total of 200 patients. Outcome of treatment was compared with respect to time to delivery from start of contractions. Prognostic variables compared here were, e.g. dilatation, parity and Bishop score. All comparisons were performed with a life table technique, both bivariate and multivariate. Parity showed a strong relation to prognosis and so did cervical dilatation. The degree of cervical dilatation as in spontaneous labor is the factor in the Bishop index that correlated best to the outcome of treatment. With the two predictors parity and dilatation, a scoring system was constructed.

Actuarial Analysis↗
PubMed2006

Physical activity and life expectancy with and without diabetes: life table analysis of the Framingham Heart Study.

OBJECTIVE: Physical activity is associated with a reduced risk of developing diabetes and with reduced mortality among diabetic patients. However, the effects of physical activity on the number of years lived with and without diabetes are unclear. Our aim is to calculate the differences in life expectancy with and without type 2 diabetes associated with different levels of physical activity. RESEARCH DESIGN AND METHODS: Using data from the Framingham Heart Study, we constructed multistate life tables starting at age 50 years for men and women. Transition rates by level of physical activity were derived for three transitions: nondiabetic to death, nondiabetic to diabetes, and diabetes to death. We used hazard ratios associated with different physical activity levels after adjustment for age, sex, and potential confounders. RESULTS: For men and women with moderate physical activity, life expectancy without diabetes at age 50 years was 2.3 (95% CI 1.2-3.4) years longer than for subjects in the low physical activity group. For men and women with high physical activity, these differences were 4.2 (2.9-5.5) and 4.0 (2.8-5.1) years, respectively. Life expectancy with diabetes was 0.5 (-1.0 to 0.0) and 0.6 (-1.1 to -0.1) years less for moderately active men and women compared with their sedentary counterparts. For high activity, these differences were 0.1 (-0.7 to 0.5) and 0.2 (-0.8 to 0.3) years, respectively. CONCLUSIONS: Moderately and highly active people have a longer total life expectancy and live more years free of diabetes than their sedentary counterparts but do not spend more years with diabetes.

Adult↗
PubMed1980

[Comparison between surgical and conservative treatment (106Ru/106Rh beta rays) of choroidal melanoma calculated by survival rate and survival time using the life table method (author's transl)].

According to the literature about 40 to 50 percent of patients with malignant melanoma of the choroid die of metastases within five years of enucleation. These figures justify the search for more effective methods and treatment. Computation of the survival rate using the life table method commonly applied in demographic studies is explained, and described by reference to the practical example of a comparison of two patient collectives. Out of 214 patients treated by enucleation, 67.6% were still alive five years later, while 90.7% of 136 patients treated with 106Ru/106Rh applicators survived the same period of time.

Choroid Neoplasms↗
PubMed1989

Prospective follow-up of cervical HPV infections: life table analysis of histopathological, cytological and colposcopic data.

A total of 532 women with established cervical HPV infection have been prospectively followed (without treatment) since 1981 for a mean of 45 (SD 21) months. The patients were examined by colposcopy, PAP smears and/or punch biopsy every 6 months. The life-table method was applied to analyze the clinical course (i.e. regression and progression) of the HPV lesions, stratified by their colposcopic pattern, PAP smear findings and grade of CIN. During the follow-up, 107 (41.8%) of 256 patients with HPV-NCIN lesion in the first punch biopsy, experienced spontaneous regression. The corresponding proportions for HPV-CIN I, HPV-CIN II and HPV-CIN III lesions were 31.1%, 34.2%, and 20.7%, respectively. In the overall comparison between these four groups, the heterogeneity in the probability of regression was statistically significant (p = 0.0005). Clinical progression was also associated significantly with the histological grade of the lesions in the first biopsy. Progression rate was only 5.8% for HPV-NCIN lesions, as compared to 12.3% for HPV-CIN I, 20% for HPV-CIN II, and 55.2% for HPV-CIN III. The probability of progression varied significantly between the four groups (p less than 0.00001). Cumulative proportion of regression was 46% for patients with PAP smear class I, 84% with class II, and 82% for those with class III, cells, i.e. PAP smear was not of value in predicting the regression. However, PAP smears predicted clinical progression (p = 0.006 overall).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1986

Comparison of methotrexate with azathioprine or 6-mercaptopurine in refractory rheumatoid arthritis: a life-table analysis.

Methotrexate (MTX) appears to be useful in patients with rheumatoid arthritis (RA) refractory to other drugs but its long-term toxicity and efficacy are uncertain. A retrospective study of MTX in such patients in comparison with the purine analogues, azathioprine and 6-mercaptopurine was made using life-table analysis. Eighty-four patients took MTX in a median dose of 7.5 mg/week whilst 55 received purine analogues, 100 mg/day (median). By 12 months, 19.3% of patients had ceased MTX due to toxicity, compared with 29.3% for purine analogues. Toxicity severe enough to warrant stopping therapy was uncommon after 8 months with either drug. At 12 months 61.5% of the MTX patients had achieved defined criteria of improvement compared with 25.6% for the purine analogues (p less than 0.05). The number of patients improving on purine analogues did not increase substantially after 6 months, whereas the number improving with MTX continued to 12 months. MTX in a low-dose regimen is useful in refractory RA and superior to low-dose purine analogues.

Actuarial Analysis↗
PubMed1983

The use of life tables and survival analysis in testing genetic hypotheses, with an application to Alzheimer's disease.

Because of the late onset of some neuropsychiatric disorders suspected to be under genetic influence, such as Alzheimer's disease, standard techniques for testing genetic hypotheses are difficult to apply to clinical data. The statistical aspects of life table methods and survival probability estimators which can be used to test such hypotheses have been neglected in the psychiatric literature. Two techniques of this kind, the Weinberg morbidity table and the Kaplan-Meier product limit estimator, are applied to real and simulated data. As estimators of lifetime incidence these methods yield roughly equivalent results for both types of data, although from a theoretical standpoint the original Weinberg estimator appears to suffer from logical defects. Parametric models may offer more definitive results, particularly when an estimator of segregation ratio is required. The clinical data in this report were gathered by interviewing relatives of Alzheimer's disease patients sampled through a nursing home survey in metropolitan Baltimore, Maryland during 1980.

Actuarial Analysis↗
PubMed1981

[Life tables].

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Asia↗
PubMed1985

A comparison of alprazolam, gefarnate and their combination in treatment of peptic ulcer patients--an application of life table analysis.

One hundred and thirty-nine patients with endoscopically confirmed peptic ulcers (gastric and duodenal) entered a double blind comparative evaluation of alprazolam (1.2 mg/day), gefarnate (300 mg/day) and their combination in treatment of peptic ulcer. Healing of ulcers was confirmed by endoscopic examinations. For evaluation of the treatment effect, the "life table" method was applied to the analysis of the data. The results revealed that ulcer healing with the combination was faster by two weeks than that with alprazolam or gefarnate alone. The difference did not reach the statistical significance in all the subjects who fulfilled the entry criteria. There was, however, a statistical difference between treatments in the patients having manifest psychic symptoms such as anxiety, insomnia and depressive mood (p less than 0.05 by generalized Kruskal-Wallis test and p less than 0.1 by Logrank test). The rate of patients who had psychic symptoms before entry and had not been cured of ulcers at the 4th week of treatment was 61% on the combination treatment as compared to 96% on the gefarnate treatment and 93% on the alprazolam treatment.

Actuarial Analysis↗
PubMed1983

Mortality study of nickel-cadmium battery workers by the method of regression models in life tables.

The mortality experienced by a cohort of 3025 nickel-cadmium battery workers during the period 1946-81 has been investigated. Occupational histories were described in terms of some 75 jobs: eight with "high", 14 with "moderate" or slight, and 53 with minimal exposure to cadmium oxide (hydroxide). The method of regression models in life tables (RMLT) was used to compare the estimated cadmium exposures (durations of exposed employment) of those dying from causes of interest with those of matching survivors in the same year of follow up, while controlling for sex, for year and age of starting employment, and for duration of employment. No new evidence of any association between occupational exposure to cadmium oxide (hydroxide) and cancer of the prostate was found.

Cadmium↗
PubMed1983

A note on life tables and nonlinear death processes.

This note is viewing survival data of a natural cohort as being generated by a possibly nonlinear, nonhomogeneous death process. It proves that the usual conditional distributions of the number of survivors at a certain age are binomial if and only if the death process is linear. Thus the customary statistical methods for the analysis of life table data are, strictly speaking, invalid whenever the underlying death process is nonlinear. For example, if a contagious disease is the cause of some or all of the deaths, the deaths will not be independent and the death process, not linear. One should then base the statistical analysis on a model for the spread of the disease rather than the routine binomial model.

Age Factors↗