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PubMed1984

[Time trends in cancer incidence in Osaka].

Changes in environments and life styles in Japan have caused the recent changes in the time trends of cancer incidence for various sites. Using the data from the Osaka Cancer Registry, time trends during 1966-80 were analysed for cancer incidence of the leading 5 sites: stomach, lung, liver, uterus and breast. Age-adjusted incidence rates of cancers of the stomach (both sexes) and uterus (invasive cancer) decreased to 75% and 64% respectively between the two periods of 1966-68 and 1978-80 while cancers of the lung, liver, and breast reached 163%, 140%, and 143 % during the same period. Decrease of stomach cancer incidence was observed in all age-groups under 79, however, not in the 25-44 age-groups among females. Analyzing the histological data in the registry, it was noticed that estimated incidence of the intestinal type of stomach carcinoma had decreased more rapidly than the diffuse type. In the 30-49 age-groups among females, no decrease was observed of the diffuse type of carcinoma. Concerning lung cancer, a marked increase was observed over 60 years of age. The age-specific incidence curves by birth cohort showed no or very small cohort effects for the population born 1920-29. Among males, percentages of adenocarcinoma and undifferentiated carcinoma have increased and that of epidermoid carcinoma decreased. The change was more marked in the age-groups younger than 59. Liver cancer showed the 3rd highest incidence rate among males and 6th among females. A rising trend in recent years was noticeable over 45 years of age among males. For the invasive uterine carcinoma, the incidence rate has been decreasing in all ages. Comparing these figures with those of whites in Connecticut or of Japanese in Hawaii, the former was higher than the latter and the difference was larger in age-groups over 40. The recent age incidence curve of breast cancer in Osaka came to be close to that in Iceland in 1930-49 when the curve had kept a constant level for age-groups after menopause. Birth cohort effect was observed for in these age classes.

Adult↗

PubMed2006

Mortality inequalities in times of economic growth: time trends in socioeconomic and regional inequalities in under 5 mortality in Indonesia, 1982-1997.

STUDY OBJECTIVE: To examine time trends in socioeconomic and regional inequalities in under 5 mortality in Indonesia during almost two decades of economic growth. DESIGN: Under 5 mortality was calculated for the total population and for subgroups by maternal education, household wealth, rural/urban residence, and island group, using the 1987, 1991, 1994, and 1997 Indonesian Demographic and Health Surveys. Inequalities were calculated using Cox proportional hazards analysis. SETTING: Indonesia, 1982-1997. Main PARTICIPANTS: 18,205, 33,907, 39,433, and 37,533 children respectively, aged under 5 years, born to women included in the above mentioned surveys. MAIN RESULTS: Under 5 mortality declined substantially during the 1980s and 1990s. Educational inequalities in under 5 mortality decreased, although not statistically significantly, from a hazard ratio of 2.00 (95%CI 1.60, 2.50) to 1.52 (95%CI 1.27, 1.82). Inequalities between urban and not electrified rural areas increased, from 1.84 (95%CI 1.48, 2.28) to 2.18 (95%CI 1.70, 2.80). Inequalities between the Outer Islands and the central islands of Java/Bali increased from 1.16 (95%CI 0.92, 1.46) to 1.43 (95%CI 1.17, 1.74). Irregular time trends were seen for inequalities by household wealth. Trends in health care use were fairly similar for the low and high educated. CONCLUSIONS: These results for education show that socioeconomic inequalities in under 5 mortality do not inevitably rise in times of rapid economic growth. Widening or narrowing of health inequalities in times of economic growth might depend on how equally this growth is distributed.

Adolescent↗

PubMed2007

Time trends of esophageal cancer in Hong Kong: age, period and birth cohort analyses.

This study was to examine the time trend of the incidence rates of esophageal cancer during the period 1979-2003 in Hong Kong and to identify the effects of year of diagnosis (period) and year of birth (cohort) on the observed time trends using regression models. Cancer incidence data were obtained from Hong Kong Cancer Registry and population data were from the Census and Statistics Department. Age-standardized incidence rates were computed by the direct method using the World population of 1966. Annual percentage change (APC) in incidence rate was calculated using nonlinear regression. Period and cohort effects were assessed using 2 separate Poisson regression models after adjusting for age. During the period 1979-2003, a steady decrease in the age-standardized incidence rate was observed for both males (APC = -3.38%, 95% confidence interval [CI]: -2.89%, -3.86%) and females (APC = -3.92%, 95% CI: -3.15%, -4.69%). The incidence rates were consistently higher among males than females. After the adjustment for age and with the period 1989-1993 or birth cohort of 1934-1938 as reference, the relative risk of more recent periods or birth cohorts significantly decreased. The age-cohort model provided a better description of the data than the age-period model. Given reasonable latency between exposures and esophageal cancer incidence, the declining birth cohort effects in the recent generations were in line with the increased intakes of fresh vegetables and decreased consumptions of alcohol drinking, tobacco smoking, and preserved foods observed in population, thus supported their importance in influencing the burden of esophageal cancer.

Adult↗

PubMedDate not supplied

Time-trends and causes of infant, neonatal and postneonatal mortality in Mexico, 1980-1990.

OBJECTIVE: This article analyzes the time-trends and causes of infant, neonatal, and postneonatal mortality in Mexico during the 1980's. MATERIAL AND METHODS: Data on infant deaths came from yearly tabulations (1980 to 1990) published by the Mexican government. Time-trends of mortality rates were determined by simple linear regression models. The parallelism test was performed for evaluating similarities in trends in neonatal and postneonatal mortality rates by causes. RESULTS: During the 1980's, infant mortality rates in Mexico declined from 40.4 to 31.1/1000 (beta = -0.791). Postneonatal mortality rates showed a strong decrease (beta = -0.892), while neonatal mortality rates were almost stationary (beta = 0.089). Significant rate decreases were observed for intestinal infections, Pneumonia and influenza and All other causes while Certain perinatal problems, Congenital defects and Nutritional deficiencies increased. No changes were observed in Acute respiratory infections. The neonatal proportional mortality showed an incremental trend accounting for 37.6% in 1980 and ascending to 48.8% in 1990 of the mortality in the first year of life. CONCLUSIONS: This analysis indicates that the reduction in infant mortality in Mexico during the 1980's was due to declining postneonatal mortality while neonatal mortality rates remain almost unchanged.

Age Factors↗

PubMed1980

Time trend analysis of unconjugated estriol concentrations in third-trimester pregnancy.

Utilizing a plasma pooling procedure to control short-term pulsatile variability of unconjugated estriol (E3) concentrations, the authors evaluated time trend curves in 42 subjects after normalizing time trend curves in 42 subjects after normalizing gestational age (GA) by a computerized algorithm. Semilogarithmic plots from individual subjects and a median plot derived from pooling the 42 subjects describe complex bimodal curves beginning with an initial steep rise at 30 to 32 weeks' GA, a peak between 32 and 34 weeks' Ga, a transient nadir at 35 weeks' GA, a second steep rise between 35 and 37 weeks' Ga, a second peak between 37 and 39 weeks' Ga, and a downward segment just prior to parturition. Predicted GAs at delivery obtained from individual curve analyses concurred with pediatric GAs within 2 weeks or less in 41 or 42 pregnancies.

Estriol↗

PubMedDate not supplied

A method of analysis of laboratory data in an epidemiological study where time trends are present.

Where data are collected over an extended period, in either cross-sectional or prospective studies, time trends in laboratory measurements can have misleading effects on observed associations, especially where it has not been possible to randomize the order of entry of participants to the study. In an ongoing prospective study of ischaemic heart disease, a modified cusum technique is used to examine the data for time trends. The paper considers a method for estimating where changes may have occurred, a method for adjusting for such changes in investigating the associations between variables and the appropriateness of making such adjustments.

Adenosine Diphosphate↗

PubMed2001

Increasing thyroid cancer incidence in Canada, 1970-1996: time trends and age-period-cohort effects.

We examined time trends in thyroid cancer incidence in Canada by age, time period and birth cohort between 1970 and 1996. Age-specific incidence rates by time period and birth cohort were calculated and age-period-cohort modelling used to estimate effects underlying the observed trends. Overall age-adjusted incidence rates of thyroid cancer doubled, from 3.3 and 1.1 per 100 000 in 1970-72 to 6.8 and 2.2 per 100 000 in 1994-96, among females and males respectively. Almost all the increase between 1970-72 and 1994-96 was due to papillary carcinoma of the thyroid. Age, birth cohort and period effects significantly improved the fit of the model for females, while age and birth cohort effects were significant determinants of the incidence among males. There were significant differences in the patterns/curvature for age, period and birth cohort effects between women and men. Our results suggest that the increases in thyroid cancer incidence in Canada may be associated with more intensive diagnostic activities and change in radiation exposure in childhood and adolescence. Temporal changes in reproductive factors among young women may explain some of the gender differences observed.

Adolescent↗

PubMedDate not supplied

Time trends of smoking cessation analyzed with six mathematical survival models.

In this paper, six mathematical models were applied to model time trends of smoking cessation. Both statistical and non-statistical methods were used and included the exponential, ideodynamic, log-logistic, Pareto, sickle and Weibull models. All models included the possibilities of both permanent abstinence and relapse to smoking. Time trends from all models were compared with data from the Multiple Risk Factor Intervention Trial (MRFIT) program. The Pareto, log-logistic, Weibull and ideodynamic models yielded satisfactory fits to the data while the sickle and exponential models did not. Even though the data used in this paper were not sufficient to distinguish among these four models, the methodology will be useful for further narrowing the model choices as additional data for the testing become available.

Adult↗

PubMed2000

Time trends for small gastric cancer in Japan.

BACKGROUND: Gastric cancer rates in Japan have been declining since the 1970s. The rate of differentiated carcinomas has decreased and that of undifferentiated carcinomas has increased. However, little is known about the time trends of small gastric cancer. The aim of this study was to investigate the trends of small gastric cancer over time in Japan. METHODS: We reviewed cases of small gastric cancer (less than 20 mm in diameter) in two groups of patients who entered the age range of 55-to-67 years 14 years apart: patients in cohort 1 (n = 66) were born between 1899 and 1912, and those in cohort 2 (n = 66) were born between 1926 and 1936. Between-group comparisons were made for macroscopic, microscopic, and histochemical findings. Mucin histochemical analysis was used to investigate gastric and nongastric phenotypes. Helicobacter pylori was also investigated by immunohistochemistry. RESULTS: There were significant decreases in the incidence of elevated carcinoma (20% in cohort 1 vs 6% in cohort 2; P < 0.05) and papillary adenocarcinoma (11% vs 2%; P < 0.05). The incidence of flat carcinomas was significantly increased (3% vs 15%; P < 0.05). The incidence of tumors surrounded by fundic gland mucosa increased (20% vs 29%), whereas that of tumors surrounded by intestinal metaplastic mucosa decreased (52% vs 41%). The rate of H. pylori infection in mucosa surrounding tumors was the same in both groups (35%). The incidence of tubular adenocarcinoma with gastric-type mucin was higher in cohort 2 (64%) than in cohort 1 (51%). CONCLUSION: The rate of tubular adenocarcinomas containing gastric type mucin has increased over time. These tumors had a tendency to develop in the fundic gland mucosa and to show less intestinal metaplasia. The H. pylori infection rate was unrelated to this time trend. In advanced gastric cancer, the differentiated carcinoma rate has decreased; however, in small gastric cancer, the rate of tubular adenocarcinoma containing gastric type mucin has increased. This suggests that tubular adenocarcinoma with gastric type mucin changes into poorly differentiated adenocarcinoma as tumors grow to advanced stages.

Journal Article↗

PubMed1990

Ischaemic heart disease among men in Norway during the period 1966-1985: two counties with different mortality time trends.

We have examined regional differences in mortality from ischaemic heart disease, including sudden, unexpected death (IHD/SUD), among Norwegian men aged 30-69 years, during the period 1966-1985. Mortality time trends were considered. The two counties with the most widely differing IHD/SUD mortality time trends were Rogaland and Oppland. Rogaland, located in south-western Norway, experienced a 24.1% IHD/SUD mortality rate decrease between 1966-1970 and 1981-1985, while Oppland, in central south-eastern Norway, experienced a mortality rate increase of 12.4%. Marked regional differences within these counties were found. The highest IHD/SUD mortality rate increase occurred in rural areas of Oppland. Urban areas of Rogaland had sharply decreasing rates. Knowledge of such regional mortality differences could provide useful information regarding aetiological factors and serve as a basis for preventive measures and health-care planning.

Adult↗

PubMed2003

[Recent time trends of myocardial infarction rates in northern Italy. Results from the MONICA and CAMUNI registries in Brianza: 1993-1994 versus 1997-1998].

BACKGROUND: Previously reported time trends of myocardial infarction rates in the MONICA Brianza 35-64-year-old population showed a clear decline in coronary heart disease mortality, mostly attributable to concurrent reductions in myocardial infarction attack rates, and to a lesser extent in 28-day case fatality. The aims of this study were to estimate time trends in more recent years (up to 1997-1998) in the same population and in the same age range, and to assess the impact of myocardial infarction among 35-74-year-old residents, an age range never investigated before in Italy using standardized population-based registers. METHODS: The myocardial infarction register in the Brianza population was resumed in 1997-1998, adopting the same standardized methods for data collection and classification of suspect coronary events as the WHO MONICA project, including the age group 65-74 years in addition to age groups usually covered. Age-specific and age-standardized rates of validated coronary mortality rates, of attack rates, and incidence rates and of 28-day case fatality were calculated. Time changes were estimated as the difference in rates. RESULTS: In comparison to the rates among 35-64-year-old residents, the 35-74 age-standardized rates of coronary event mortality in the biennium are more than 3 times higher in women and more than twice in men. Similarly, the attack and incidence rates increased respectively from 243 to 381 and from 197 to 292 per 100,000 in men, from 38 to 107 and from 33 to 87 per 100,000 in women. Statistically significant reductions are observed in coronary death rates, myocardial infarction attack rates and 28-day case-fatality rates between 1993-1994 and 1997-1998 in men. Analogous but not statistically significant changes are reported for women. CONCLUSIONS: In the Brianza MONICA population in the second half of the 1990s, coronary event death rates continued to decrease. In contrast with trends observed in previous years, the prominent quote of the reduction is attributable to case-fatality rates in the acute phase.

Adult↗

PubMed2000

Surgery for non-small cell lung cancer: postoperative survival based on the revised tumor-node-metastasis classification and its time trend.

OBJECTIVE: To clarify results of surgery for non-small cell lung cancer (NSCLC) based on the new tumor-node-metastasis (TNM) classification revised in 1997 and its time trend. METHODS: A total of 921 patients operated from 1980-1994 were retrospectively reviewed. For analysis of time trend, they were grouped into three periods by the year of operation (period (1): 1980-1984, period (2): 1985-1989, and period (3): 1990-19-94). RESULTS: Concerning patients' characteristics, recent increase in the ratio of patients whose tumor was discovered at mass screening (31% in period (1), 40% in period (2), and 50% in period (3)), and increase in the ratio of p-stage IA patient (16, 20, and 29%, respectively) were marked. Decrease in the ratio of operation-related death and the ratio of exploratory thoracotomy was significant. Concerning level of operation, decrease in the ratio of pneumonectomy, increase in the ration of sublober resection and that of tracheal or bronchoplastic procedures were significant. Postoperative survival for all patients was significantly better in period (2) or (3) than that in period (1); no significant difference was demonstrated between period (2) and (3) (5-year survival rates: 35% for period (1), 56% for period (2), and 56% for period (3)). Stratified p-stage, improvement of postoperative survival in recent years was demonstrated in p-stage IIA, IIB, IIIA, and IIIB diseases. CONCLUSIONS: Postoperative survival for all NSCLC patients has been improved with significant increase of early-stage (p-stage IA) patients. Concerning level of resection, recent increase in patients who underwent sublobar resection and bronchoplastic procedures was marked.

Adult↗

PubMed1998

Bidirectional case-crossover designs for exposures with time trends.

In the case-crossover design (Maclure, 1991, American Journal of Epidemiology 133, 144-153), only cases are sampled, and risk estimates are based on within-subject comparisons of exposures at failure times with exposures at times prior to failure, using matched case-control methods. While the design provides considerable advantages, unidirectional retrospective control sampling (selecting control times only prior to failure) can cause risk estimates to be confounded by time trends in exposure. However, when subsequent exposures are not influenced by failures, as in studies of environmental exposures such as air pollutants, it is possible to determine at times postfailure what a subject's level of exposure would have been had the subject not failed. We describe a bidirectional case-crossover design in which exposures at failure are compared with exposures both before and after failure. Simulation analyses show that relative risk estimates are resistant to confounding by time trend. We also extend the method to studies involving multiple failure times.

Absenteeism↗

PubMed2002

Time trends in organ position and volume in patients receiving prostate three-dimensional conformal radiotherapy.

Using multiple computed tomography (CT) scans, 50 patients undergoing prostate radiotherapy were tested for clinically significant time trends in the target and surrounding critical structures. Significant trends were observed toward increasing bladder volume and increasing bowel-to-planning target volume separation; however, no trends were observed in the prostate, seminal vesicles, or rectum. The subset of patients undergoing hormone therapy was also tested and did not independently exhibit any significant time trends.

Androgen Antagonists↗

PubMed2001

Time trend analysis of gastric cancer incidence in Japan by histological types, 1975-1989.

Since different histological types (HT) of gastric cancer (GC) may differ in their aetiology, time trend analysis by HT may afford an insight into aetiology. From the Gastric Cancer Registry of Japan, 161 067 cases diagnosed were retrieved between 1975 and 1989 to calculate the annual relative frequencies, stratified by age group and sex, of HT according to the Lauren and the Japanese Research Society for Gastric Cancer (JRSGC) classifications. Age- and sex-specific incidence rates by HT were estimated by multiplying the corresponding national cancer incidence rates of GC by the relative frequencies. Logistic regression models stratified by sex and age group were fitted to determine the time trends of HT. Using the Lauren classification, a decreasing trend of the intestinal type and a stable trend of the diffuse type were found. By the JRSGC classification, significant decreasing trends for most age groups were found for papillary and mucinous adenocarcinomas. Tubular adenocarcinomas (well differentiated type) showed a decreasing trend only in younger age groups. Tubular (moderately differentiated type), poorly differentiated adenocarcinomas, and signet ring cell carcinoma were statistically stable during the period. Considering changes in lifestyles of the Japanese, the result suggests that there are three aetiological types of GC.

Adult↗

PubMed1997

Time trends in serum cholesterol before cancer death.

Following evidence of an association between low serum cholesterol and cancer from several prospective studies, this paper concentrates on individual time trends in serial measurements of serum cholesterol before a cancer-related death. The Framingham Heart Study contains repeated measurements of cholesterol at approximately 2-year intervals in 5,209 subjects, of whom 539 died from cancer during 30 years of follow-up. We quantify (1) the change in serum total cholesterol level before cancer death, and (2) the association between fall in serum total cholesterol and odds of cancer death. The mean fall in serum total cholesterol in the 4- to 6-year period before cancer death is 8.06 (95% confidence interval = 4.58-11.54) mg per dl, with some evidence of lowered cholesterol before that period. This pattern is corroborated by evidence of a substantially increased odds of cancer death if a large fall in cholesterol occurs over any 4- to 6-year period. We suggest that these time trends can plausibly be attributed to the effects of prevalent cancer on lowering serum cholesterol; our findings add weight to the argument that the low cholesterol-cancer mortality relation does not arise because of any causal contribution of low serum total cholesterol to the risk of cancer.

Age Distribution↗

PubMed2001

Time trends of major coronary risk factors in a northern Italian population (1986-1994). How remarkable are socioeconomic differences in an industrialized low CHD incidence country?

BACKGROUND: The goals are to estimate time trends (1986-1994) of major coronary risk factors in an industrialized low CHD incidence population and to assess education class (EC) differences in risk factor prevalence and in time trends. METHODS: Three population surveys were conducted in 1986-1987, 1989-1990 and 1993- 1994 on independent and two-stage age- and gender-stratified random samples (1906 men and 1941 women) of 35-64 year old residents of Brianza, an affluent region of northern Italy. The protocol for data collection, clinical measurements and biochemical determinations adhered to the WHO MONICA manual and underwent repeated quality control assessments. EC were identified according to gender- and 5-year birth-cohort specific tertiles. RESULTS: In the initial, middle and final surveys 1258, 1259 and 1330 subjects were enrolled, corresponding to participation rates of 70.1%, 70.3% and 74.3%, respectively. Over the 8-year period, in men systolic blood pressure and smoking habits declined, body mass index and serum total cholesterol increased. In women systolic blood pressure showed a constant reduction, total cholesterol and BMI increased and the prevalence of smokers remained stable. Overall inverse associations with EC were found for body mass index, for prevalence of cigarette smokers in men and for systolic blood pressure in women. Decreases in blood pressure were more evident in the lowest EC. Cigarette smoking was on the decline in the higher EC in men. BMI and total cholesterol increased in all EC with the notable exception of the 'low' EC in women. CONCLUSIONS: Favourable changes of the risk factor profile in the low socio-economic classes may have contributed to reduce CHD rates in this population. Specific policies oriented to lowest socio-economic classes are needed to continue to combat the smoking epidemic.

Adult↗

PubMed2002

Pattern and Time Trends of Stomach Cancer in Asia from 1950-99.

Background: As there is a lack of data on stomach cancer disease in Asia, the aim of the present study was to examine patterns and time trends for this neoplasm in Asian countries. Methods: A descriptive study was designed to examine the cancer pattern and time trend and to calculate the annual change in mortality and incidence of stomach cancer at 5-year intervals. Data were derived from the WHO Mortality Database, and Cancer Incidence in Five Continents. Results: The highest rates of stomach cancer mortality and incidence (ASR) were observed in Japan, followed by the Republic of Korea, and China, the lowest rates being observed in Thailand. The highest to lowest ratios were 50 and 32 for mortality and 120 and 45 for incidence in males and females, respectively. A decreased trend of mortality was found in all 16 countries where mortality data was available, however, before the decrease, an increased trend was found in Japan in the 1950s and in Sri-Lanka in the 1950-60s. In spite of a significant decrease in mortality nationwide in Japan, an increased trend of stomach cancer incidence was found in Hiroshima (ASR + 7.4 in males and + 1.5 in females for each 5-year period). Discussion: There are very large geographical differences in risk factors of stomach cancer from country to country, and these risk factors are still highly prevalent in specific areas of Asia. Further ecological study with emphasis on host and environmental factors for stomach cancer in Asian countries are strongly recommended.

Journal Article↗