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PubMedDate not supplied

Age-period-cohort analysis of lung cancer mortality in Taiwan, 1966-1990.

The specific aim of this study was to examine the effects of age, calender period of death, and birth cohort in lung cancer mortality in Taiwan over the period 1966-1990. A log-linear model modified from the method of Osmond and Gardner was used. Age is the most important predictor of lung cancer mortality according to the model. The oldest age group of 75-79 years old had a lung cancer mortality 185.3 and 79.2 times those for the youngest age group of 30-34 for males and females, respectively. There was also a significant cohort effect. The birth cohorts at the highest risk of lung cancer death were those born around 1931 for males and 1921 for females. A leveled off or declined trend of lung cancer mortality was observed for more recent cohorts. Parameters of the period factor showed an increasing lung cancer mortality from 1966 to 1990. In addition to the adverse effect of cigarette smoking, dietary and environmental factors should be taken into consideration in interpreting the results.

Adult↗
PubMed2006

Up-to-date estimates of cancer patient survival even with common latency in cancer registration.

In an era of ongoing improvement in cancer patient survival, available long-term survival figures from cancer registries are often outdated and too pessimistic for two reasons: first, delay in availability of cancer registry data, typically in the order of a few years, and, second, application of cohort-based methods of survival analysis, which provide survival estimates for patients diagnosed many years ago. We developed a model-based period analysis approach aimed to overcome both problems. We provide extensive empirical evaluation of our approach by comparing its performance with that of previously available methods for monitoring of 5- and 10-year relative survival, with the use of data from the nationwide Finnish Cancer Registry of 490,279 patients ages >/=15 years and diagnosed with one of 20 common forms of cancer between 1953 and 1997. We show that, in most cases, the model-based approach predicts 5- and 10-year relative survival expectations of newly diagnosed patients quite closely and much better than any of the previously available methods, including standard period analysis. We conclude that the model-based approach may enable deriving up-to-date cancer survival rates even with the common latency in availability of cancer registry data.

Female↗
PubMed1996

Enhanced period-peak analysis of electro-encephalograms using a fast sinc function.

In an effort to reduce the memory space and processing time required by fast Fourier transforms, enhanced period-peak detection is investigated. The method is based on a combination of Fourier transforms and period-peak detection. The signal is considered as a train of truncated sinusoidal functions. Each truncated sinusoidal function is limited by two successive local extrema. The Fourier transform of the truncated sinusoidal function is a sinc function. The summation of these sinc functions yields an approximate frequency spectrum of the signal.

Algorithms↗
PubMedDate not supplied

[Age-period-cohort analysis of mortality caused by ischemic cardiopathy in Spain 1965-1985].

With the objective of studying the temporal evolution of ischaemic cardiopathy (IC), or coronary heart disease mortality, in Spain, we carried out a cohort analysis with conventional graphic techniques and modern statistical methods. This permits better understanding and quantification of the age-period-cohort effects and identification of the potential factors operating upon them. To this end, loglineal (Poisson regression) models were constructed of the IC mortality rates for both sexes, using the GLIM package, in which the regression coefficients are the natural Relative Risk (RR) logarithms of the various age groups (35-74 years), period of death (1970-1985) and birth cohort (1985-1960) with respect to the reference group mortality, controlled by the effect of other groups. In respect of the results, the maximum RR value corresponds to decrease year 1975, and falls progressively to 1985, though at all times remaining above the 1970 value. The effect of 1985, though less than 1980, does not present significant differences from the latter. Nevertheless, no clear cohort effect was found. As a probable explanation for the pattern observed, this would suggest recent changes in life style and in medical attention. There is a discussion of the consistency of the models selected with the graphical results and with present knowledge of the natural history of IC and with the evolution of its determining factors, together with validation of the models. In summary, the IC mortality patterns observed show an increase up to the mid-seventies, and stabilization from that date onwards, in all age and sex groups, which is consistent with an age-period effect.

Adult↗
PubMed2001

Age-period-cohort analysis of lung cancer mortality in Japan, 1960-1995.

The mortality data on lung cancer in Japan from 1960 to 1995 was analysed based on an age-period-cohort (APC) model. Though the APC model has an 'identifiable problem' caused by the relationship of age, period and cohort parameters, non-linear components of them revealed their original (separated) effects. They were: (1) non-linear age effects had a peak in 55-59 and 60-64 years old in males and 50-54 in females, (2) non-linear period effects were very small in both genders, (3) non-linear age and period effects were small enough to neglect compared with their linear effects, and (4) there were five parts of trends in Japanese lung cancer mortality in both genders in the non-linear birth cohort effects. The 1961-65 birth cohort effect seemed to increase differently from previous birth years. This trend should be monitored carefully.

Adult↗
PubMed2004

Surveillance of hazardous materials events in 17 states, 1993-2001: a report from the Hazardous Substances Emergency Events Surveillance (HSEES) system.

BACKGROUND: Thousands of acute hazardous materials (HazMat) releases occur annually throughout the United States. To prevent human exposure and resulting injuries, it is critical to understand the frequency with which these releases occur, the locations involved, the industries associated, and the specific substances being released. METHODS: HazMat events data from the Agency for Toxic Substances and Disease Registry's Hazardous Substances Emergency Events Surveillance (HSEES) system were analyzed for frequency and locations of occurrence, major industry categories and sub-categories involved, and substances released. The data analyzed were collected from 17 participating state health departments for 1993 through 2001. RESULTS: During 1993 through 2001, 53,142 HazMat events occurred. Of the 17 states analyzed, Texas had the most releases, comprising 38.3% of all HSEES events. Of the 14 major US Census industry categories analyzed, the manufacturing category had the highest percentage of events (48.7%) followed by transportation, communication, and other public utilities (27.5%). Of the 10 states that participated during the entire analysis period, the numbers of events increased 64.3%. Twelve of 14 major industrial categories experienced increases in numbers of events over the analysis period, while public administration and active duty military events decreased. The substances released most frequently overall included ammonia, sulfur dioxide, and sulfuric acid, respectively. CONCLUSIONS: The HSEES data appear to reflect an upward trend in the occurrence of hazardous HazMat events. While it is difficult to definitively conclude whether this trend is due to more events actually occurring or from other factors, reviewing historical HazMat data may help communities, government agencies, and industries prevent or better prepare for potential events in the future.

Emergencies↗
PubMed2006

Age-period-cohort analysis of cervical cancer incidence in Hong Kong from 1972 to 2001 using maximum likelihood and Bayesian methods.

OBJECTIVE: To examine the secular effects of opportunistic screening for cervical cancer in a rich, developed community where most other such populations have long adopted organised screening. DESIGN, SETTING, AND PARTICIPANTS: The analysis was based on 15 140 cases of invasive cervical cancer from 1972 to 2001. The effects of chronological age, time period, and birth cohort were decomposed using both maximum likelihood and Bayesian methods. RESULTS: The overall age adjusted incidence decreased from 24.9 in 1972-74 to 9.5 per 100,000 in 1999-2001, in a log-linear fashion, yielding an average annual reduction of 4.0% (p<0.001) during the 30 year period. There were two second order and thus identifiable changes: (1) around the mid-1920s cohort curve representing an age-period interaction masquerading as a cohort change that denotes the first availability of Pap testing during the 1960s concentrated among women in their 40s; (2) a hook around the calendar years 1982-83 when cervical cytology became a standard screening test for pregnant women. CONCLUSIONS: Hong Kong's cervical cancer rates have declined since Pap tests first became available in the 1960s, most probably because of increasing population coverage over time and in successive generations in a haphazard fashion and punctuated by the systematic introduction of routine cytology as part of antenatal care in the 1980s.

Adult↗
PubMed2005

Isolate removal methods and methicillin-resistant Staphylococcus aureus surveillance.

The effect of duplicate isolate removal strategies on Staphylococcal aureus susceptibility to oxacillin was compared by using antimicrobial test results for 14,595 isolates from statewide surveillance in Hawaii in 2002. No removal was compared to most resistant and most susceptible methods at 365 days and to the National Committee for Clinical Laboratory Standards (NCCLS) and Cerner algorithms at 3-, 10-, 30-, 90-, and 365-day analysis periods. Overall, no removal produced the lowest estimates of susceptibility. Estimates with either NCCLS or Cerner differed by <2% when the analysis period was the same; with either method, the difference observed between a 90- and a 365-day period was <1%. The effect of duplicate isolate removal was greater for inpatient than outpatient settings. Considering the ease of implementation and comparability of results, we recommend using the first isolate of a given species per patient to calculate susceptibility frequencies for S. aureus to oxacillin.

Anti-Bacterial Agents↗
PubMed2004

Age-period-cohort analysis of breast cancer mortality rates in Andalucia (Spain).

BACKGROUND: The aim of this paper is to analyse breast cancer mortality in Andalucia (Spain) between 1975 and 1999 based on age-period-cohort. PATIENTS AND METHODS: Mortality data were obtained from the Mortality Registry of Andalucia. Deaths and population were divided into 13 age groups and five 5-year periods. From this, age-specific mortality rates for 17 birth cohorts were computed. These were plotted and fitted to Poisson regression models to assess age, period and cohort effects. RESULTS: The best fit was found for the complete model, which simultaneously considered the effects of age-period-cohort. Cohort effects were found to be more important than period effects in terms of model fit. CONCLUSION: These effects were manifest as a seemingly consistent increase in the relative risk of breast cancer mortality with a three-fold increase in women born in the 1950s relative to those born in the 1890s.

Adult↗
PubMed2000

Observer variations in short period spectral analysis of heart rate variability.

25% of the corresponding mean LF/HF ratio. The smallest interobserver variations were found for the 'fixed frequency' method. The data showed that it is advantageous to select the 3-min ECG periods but not to select the frequency regions. Selection of the latter led to an increase in interobserver variation. The results of this study give a realistic impression of the intrasubject and interobserver variation to be expected when measuring the LF/HF ratio. This variation is considerable.

Analysis of Variance↗
PubMed1990

Age-period-cohort analysis of pancreatic cancer mortality in Taiwan, 1971-1986.

Interest has recently emerged about the increasing trend of pancreatic cancer mortality in Taiwan, particularly in the elderly. The mortality data of pancreatic cancer over the period 1971-1986 for males and females aged 40-84 in Taiwan were analysed using a log-linear Poisson model to examine the effects of age, calendar period of death, and birth cohort. This age-period-cohort model provides a summary guide for the reading and interpretation of cancer mortality trends. Age is the strongest factor in predicting pancreatic cancer mortality according to the models; the oldest age group 80-84 years old has 14.5 times the risk of the youngest age group 40-44. The cohort effect is also of particular interest because the generation at greatest risk for pancreatic cancer in both sexes, is the one born between 1917 and 1926, and a declining trend is observed thereafter for more recent cohorts. Parameters of the period factor show no observable trend before 1975, followed by a significantly increasing risk in the subsequent time period. However, the drop of pancreatic cancer mortality over all age groups between 1985-86 is puzzling and a further study to monitor the secular trends in the following years is warranted.

Adult↗
PubMed2003

Are patients diagnosed with breast cancer before age 50 years ever cured?

PURPOSE: Breast cancer diagnosed before the age of 50 years has become a common disease in many developed countries. Although average remaining life expectancy in the affected age groups is usually several decades, data regarding survival perspectives beyond 10 to 20 years after diagnosis are sparse. The aim of this study was to assess long-term survival in a large population-based sample of patients diagnosed with breast cancer before age 50 years. PATIENTS AND METHODS: Relative survival within up to 40 years after diagnosis was assessed for cohorts of women diagnosed with breast cancer before age 50 years and notified to the nationwide Finnish Cancer Registry within various time intervals since 1953. In addition, up-to-date estimates of 40-year relative survival were obtained by exclusively looking at the survival experience of breast cancer patients in recent years (1993 to 1999) using period analysis, a new method of survival analysis. RESULTS: Prognosis of patients diagnosed with breast cancer before age 50 years has considerably improved during the past decades. According to the latest estimates from period analysis, cumulative 40-year relative survival is now approximately 43% for all cancers combined, 57% for localized cancers, and 24% for cancers with regional tumor spread. Nevertheless, patients diagnosed with breast cancer before age 50 years continue to have increased mortality throughout at least four decades after diagnosis. This applies even if breast cancer is diagnosed in a localized stage and in the absence of a second primary breast cancer. CONCLUSION: Despite major improvement in prognosis over time, breast cancer occurring among patients who are younger than 50 years remains a chronic disease that affects prognosis for decades.

Adult↗
PubMed1978

Analysis of periodic changes in ventilation in new-born infants.

1. Ventilation was recorded in thirty term infants during the first week after delivery using the trunk plethysmograph, during periods of rapid eye movement sleep (r.e.m.) and quiet sleep (n.r.e.m.). 2. Continuous histograms of tidal volume (VT) and instantaneous respiration rate (f) were samples at 0.5 sec intervals, passed through a digital filter to remove long-term trends in the data, and then subjected to frequency analysis. 3. In all the infants oscillations in VT and f were detected, with mean periods varying from 6.7 to 12.5 sec. The amplitude of these oscillations was higher during r.e.m. than n.r.e.m. sleep in all the infants. 4. The oscillations in VT tended to be out of phase with those for f, particularly during n.r.e.m. sleep; this contrasted with in-phase oscillations in VT and f found during periodic breathing in an additional six premature infants studied.

Humans↗
PubMed1990

Computer detection and analysis of periodic movements in sleep.

Standard polysomnography (PSG) and electromyographic (EMG) recording of the right and left anterior tibial muscles by Medilog 9000 recorder was carried out in 10 patients with periodic movements in sleep (PMS). The analog EMG signals and the sleep data from the Oxford ss90III sleep stager were fed into an IBM compatible personal computer for automatic detection and analysis using specific criteria to define the leg events, the interevent interval, the number of epochs (greater than 30 jerks), and the number of bursts (4 to 29 jerks). The results of automatic analysis were compared with data obtained from visually scored paper PSG. The total number of leg jerks detected by visual scoring was 2,812 and by automatic scoring was 2,789. The mean duration of the leg jerks 2.77 s [standard deviation (SD), 1.22] and the mean inter-interval event duration was 27.3 s (SD, 14.7). The total numbers of epochs scored visually was 35 and scored automatically was 33. The correlation co-efficient to the line of identity was 0.8 (p less than 0.005). The sensitivity of automatic scoring was 94% and the specificity was 85%. Automatic detection and analysis of PMS can provide an objective method for the study of several aspects of this disease that are still not yet fully understood.

Adult↗
PubMed1996

[Analyses of rhythms of the body temperature in free running in rats].

We have previously observed a light-induced suppression of circadian rhythms of body temperature and locomotor activity in 50/55 male Sprague Dawley rats (Am. J. Physiol., 1995). This study presents a description of 4 records of body temperature obtained by telemetry and compares three methods of period analysis (Fourier analysis, autocorrelation and cosinor). In case of persistant circadian rhythms, Fourier analysis and cosinor method agree and allow description of rhythm parameters. However, in case of an alteration of the circadian system in continuous light, these 2 methods can disagree on the dominant period. Autocorrelation analysis permits to conclude on the absence of circadian and ultradian rhythmicity. These results demonstrate the necessity to associate several methods for period analysis and plaids for the development of a strategy for data processing of longitudinal time series.

Animals↗
PubMed2006

Difference in the incidence trend of nasopharyngeal and oropharyngeal carcinomas in Taiwan: implication from age-period-cohort analysis.

Lifestyle factors are considered important for the pathogenesis of both nasopharyngeal and oropharyngeal carcinomas. In Taiwan, the incidence of nasopharyngeal carcinoma gradually decreased over the past 20 years, whereas that of oropharyngeal carcinoma increased rapidly. To compare the incidence trends of nasopharyngeal and oropharyngeal carcinomas in Taiwan, the age-period-cohort model was used to analyze epidemiologic data from 1981 to 2000 obtained from the Taiwan Cancer Registry. The calendar time period of 1986 to 1990 and the 1931 to 1940 birth cohort were used as reference groups for estimates of relative risk. For nasopharyngeal carcinoma, the incidence seemed to decrease in most age groups and was more prominent in women (30%) than in men (23%). For oropharyngeal carcinoma, the incidence increased in all age groups and was more prominent in men (391.4%) than in women (59.2%). Cohort effect was found for both nasopharyngeal and oropharyngeal carcinomas. The relative risk of nasopharyngeal carcinoma for the 1971 to 1980 birth cohort was 0.38 for women and 0.68 for men. The relative risk of oropharyngeal carcinoma for the 1971 to 1980 cohort was 45.67 for men and 2.69 for women. Change in lifestyle seemed to be an important factor for the difference in the incidence trend between nasopharyngeal and oropharyngeal carcinomas and between men and women.

Adult↗