Relationships of age, period, and birth cohort for stomach cancer mortality in Japan

The mortality data on stomach cancer in Japan during 1955 to 1980 were analyzed by the use of an age-period-cohort model. Although the model could not give a unique solution of age, period, and cohort parameters, several sets of estimates of the parameters clarified particular features of each effect. Within a plausible range, the features were as follows. The period parameter underwent linear change from 1965 to 1980 for males and from 1970 to 1980 for females. The cohort parameters decreased birth cohort by birth cohort, at least among those who were born after 1891. The curve of the age parameter in females showed a shoulder around age 40 and a subsequent upward slope to age 80, while that in males was unimodal. The curve in females was compatible with the idea that there might be two different main entities in stomach cancer. The model also gave estimates of future trends in stomach cancer mortality under the assumption that there would be no additional change in period effect other than that expected from the recent quinquennia. The number of deaths from stomach cancer in males would be rather stable until 2000, and that in females would decline slightly. The age-adjusted and crude mortality rates would continue to decrease at least until 2000.     

An age, period and cohort analysis of pleural cancer mortality in Europe.

Death certification data from pleural cancer in eight European countries providing data to the World Health Organization database over the period 1970-1994 were analysed using a log-linear Poisson model to disentangle the effects of age, birth cohort and period of death. The age effect reached values between 10 and 15/100,000 males at age 80-84 in most countries, except Hungary (6.7), Switzerland (18.0), France (20.6) and the Netherlands (36.5). Cohort effects were steadily and appreciably upwards in all countries up to the generations born in 1940 or 1945, and levelled off for the 1950 cohort, except in Hungary, where persistent rises were observed. Thus, most rises in pleural cancer mortality in Europe were on a cohort of birth basis. Since most pleural cases were asbestos-related mesotheliomas, and since asbestos has an early-stage effect on subsequent mesothelioma risk, exposure early in life is important for determining the subsequent mesothelioma risk of each generation. Consequently, the data indicate that the peak mortality from pleural cancer in most western European countries will be reached in the first decades of the 21st century, i.e. around 2010-2020, when the generations born between 1940 and 1950 will reach the peak age for mesothelioma incidence and mortality. This contrasts with US data, where the peak of pleural cancer incidence has been reached at the end of the 20th century, and reflects a delay in adopting adequate prevention measures since the 1940-1945 generations entered the workforce in the 1960s, when cancer risk from asbestos exposure was already recognized.     

栖霞市胃癌死亡率与年龄、时期和出生队列三因素关系的定量分析

目的 :研究年龄、时期和出生队列对疾病的效应的定量分析方法。方法 :采用Kupper数学模型 ,用矩阵的三角分解法求解 ,对三因素的各个亚层成分效应大小的定量参数估计。结果 :1970～ 1994年栖霞市胃癌死亡率前 10年上升后 15年呈平稳下降趋势。这种现象与时期因素关系不大 ,主要与 65～ 85岁及以上年龄组和 1910～至 1890～五个出生队列人群暴露于胃癌的危险性因素程度高有关。结论 :栖霞市胃癌死亡率的变化趋势与出生队列因素有关     

Effects of age, birth cohort and period of death on Swiss cancer mortality, 1951-1984

Swiss death certification data over the period 1951-1984 for total cancer mortality and 30 major cancer sites in the population aged 25 to 74 years were analysed using a log-linear Poisson model with arbitrary constraints on the parameters to isolate the effects of birth cohort, calendar period of death and age. The overall pattern of total cancer mortality in males was stable for period values and showed some moderate decreases in cohort values restricted to the generations born after 1930. Cancer mortality trends were more favourable in females, with steady, though moderate, declines in both cohort and period values. According to the estimates from the model, the worst affected generation for male lung cancer was that born around 1910, and a flattening of trends or some moderate decline was observed for more recent cohorts, although this decline was considerably more limited than in other European countries. There were decreases in cohort and period values for stomach, intestine and oesophageal cancer in both sexes and (cervix) uteri in females. Increases were observed in both cohort and period trends for pancreas and liver in males and for several other neoplasms, including prostate, brain, leukaemias and lymphomas, restricted, however, for the latter sites, to the earlier cohorts and hence partly attributable to improved diagnosis and certification in the elderly. Although age values for lung cancer in females were around 10-times lower than in males, upward trends in female lung cancer cohort values were observed in subsequent cohorts and for period values from the late 1960's onwards. Therefore, future trends in female lung cancer mortality should continue to be monitored. The application of these age/period/cohort models thus provides a summary guide for the reading and interpretation of cancer mortality trends, although it cannot replace careful inspection of single age-specific rates.     

Trends in breast cancer mortality among Swedish women 1953-92: analyses by age, period and birth cohort.

Trends in breast cancer mortality among Swedish women were explored on the basis of all 51,048 deaths in women 30-89 years of age in Sweden during the period 1953-92. The age-standardised mortality rates were virtually unchanged during the observation period (with a mean of 32 deaths per 100,000 females and year), as were age-specific rates. In age-period-cohort analyses, age alone explained almost all of the variation in the rates. The effects of period and cohort were statistically significant, but very modest. Cohort effects seemed to explain more than period effects, and a weak downward trend starting with women born in 1883-92 was noted. A change in 1981 in the policy to classify the causes of death from the death certificates seemed to entail an artificial lowering of the mortality rates in women older than 75 years. It is concluded that breast cancer mortality in Sweden during the last 40 years has been remarkably stable, in spite of a substantial and constant increase in the incidence. This divergence between mortality and incidence reflects improved survival, which could in part be explained by earlier detection and more efficient treatment, or by an increasing occurrence of less aggressive tumours.     

Italian mediterranean index and risk of colorectal cancer in the Italian section of the EPIC cohort

Colorectal cancer is among the commonest cancers worldwide. Dietary factors have been linked to colorectal cancer risk, however, few studies have evaluated the relationship between a priori dietary patterns and colorectal cancer risk. We evaluated the effect of adherence to a Mediterranean dietary pattern, as measured by the Italian Mediterranean Index, on the risk of colorectal cancer in the 45,275 participants of the Italian section of the EPIC study who completed a dietary questionnaire. Hazard ratios (HRs) with 95% confidence intervals (CIs) for colorectal cancer in relation to categories of Italian Mediterranean Index score were estimated by multivariate Cox models adjusted for known risk factors, on the whole cohort, on men and women and according to cancer subsite. During a mean follow‐up of 11.28 years, 435 colorectal cancer cases were identified. The Italian Mediterranean Index was inversely associated with colorectal cancer risk (HR: 0.50; 95% CI: 0.35–0.71 for the highest category compared to the lowest, P‐trend: 0.043). Results did not differ by sex. Highest Italian Mediterranean Index score was also significantly associated with reduced risks of any colon cancer (HR: 0.54, 95% CI: 0.36–0.81), distal colon cancer (HR: 0.44, 95% CI: 0.26–0.75) and rectal cancer (HR: 0.41, 95% CI: 0.20–0.81), but not of proximal colon cancer. These findings suggest that adherence to a Mediterranean diet (as measured by the Italian Mediterranean Index) protects against colorectal cancer in general but not against cancer developing in the proximal colon.     

Breast cancer risk by age at birth, time since birth and time intervals between births: exploring interaction effects

In a Norwegian, prospective study we investigated breast cancer risk in relation to age at, and time since, childbirth, and whether the timing of births modified the risk pattern after delivery. A total of 23,890 women of parity 5 or less were diagnosed with breast cancer during follow-up of 1.7 million women at ages 20-74 years. Results, based on Poisson regression analyses of person-years at risk, showed long-term protective effects of the first, as well as subsequent, pregnancies and that these were preceded by a short-term increase in risk. The magnitude and timing of this adverse effect differed somewhat by birth order, maternal age at delivery and birth spacing. No transient increase in risk was seen shortly after a first birth below age 25 years, but an early first birth did not prevent a transient increase in risk after subsequent births. In general, the magnitude of the adverse effect was strongest after pregnancies at age 30 years or older. A wide birth interval was also related to a more pronounced adverse effect. Increasing maternal age at the first and second childbirth was associated with an increase in risk in the long run, whereas no such long-term effect was seen with age at higher order births.     

Age at first birth, dietary practices and breast cancer mortality in various Italian regions

Breast cancer death certification rates in Italy showed a consistent geographic variation, with approximately a 2-fold ratio between the highest rates registered in Northern (and richer) regions, and the lowest ones in the South. This variation in breast cancer mortality was positively and strongly correlated with mean age at first birth (r = + 0.73). This positive correlation could not be totally explained by several other economic or dietary variables considered, though some of them substantially reduced the strength of the association. Breast cancer mortality rates were found to be positively correlated with milk, meat and sugar consumption, and negatively with pasta, thus confirming previous studies on national or international scales. These correlation coefficients, however, were considerably reduced after controlling for mean age at first birth. Further, when allowance was made for economic variables and age at first birth, only the correlation coefficients for milk and cheese remained significantly positive. Thus, the evidence from this study suggests that the Italian geographical correlations between breast cancer mortality and dietary variables may be largely explained in terms of reproductive factors, though there may be some effect of dietary variables on breast cancer risk as well.     

A cohort study of tobacco use,diet, occupation,and lung cancer mortality

In 1966, a cohort of White males aged 35 or over, who were policy-holders with the Lutheran Brotherhood Insurance Society (United States), completed a mail questionnaire on tobacco use, diet, and demographic characteristics. During the 20 years of follow-up, 219 lung cancer deaths occurred. Besides the strong relationship with cigarette smoking, we observed an effect on lung cancer risk among current users of cigars or pipes who were nonsmokers of cigarettes (relative risk [RR]=3.5, 95 percent confidence interval[CI]=1.0–12.6) or who were past/occasional users of cigarettes (RR=2.7, CI=1.4–5.3). In addition, elevated risks (from 1.5 to 2.6) of lung cancer were found among craftsmen and laborers, with the highest risks among subjects who worked in the mining or manufacturing industry. No association between current (as of 1966) use of beer or hard liquor and lung cancer was observed, although past users were at elevated risk. An inverse association between lung cancer and intake of fruits was observed, and risks of lung cancer were lower among persons in the highest dietary intake quintiles of vitamins A and C. Except for oranges, however, none of the inverse associations with fruits or dietary nutrients had statistically significant trends. The findings from this cohort study add to the evidence of an adverse effect of cigar/pipe smoking and possibly protective effect of dietary factors on lung cancer risk.     

Correlations between cancer mortality rates from various Italian regions

Death certification rates from 17 non-sexual and 4 sexual cancers were used to examine patterns of correlation between various cancers within the 20 Italian regions. A large number of strongly positive correlations emerged, reflecting the geographical distribution of cancer mortality in Italy which shows substantially higher rates for several common sites in northern areas. The most notable findings were the high positive correlations between various tobacco-related cancers in both sexes (however somewhat higher in males), the positive correlations between most intestinal sites and between a well defined group of other cancers including intestines in both sexes, breast and ovary in females and prostate in males, previously described in several widely heterogeneous populations. Various alcohol-related cancers showed high positive coefficients in males but not in females. Several suggestions which emerged from previous correlation studies but which generally lacked convincing biological or epidemiological consistency were not confirmed by the present data. Conversely, a few strong correlations emerged in the present study which are not explainable in terms of available knowledge of the causes of cancer, or obvious confounding. Though probably incidental, the existence of these correlations between cancers with widely heterogeneous or largely undefined etiology is still an indirect indication that these neoplasms are largely avoidable, since it is unlikely that the same genetic determinants are strongly associated with such different malignancies.     

Birth weight and risk of breast cancer in a cohort of 106,504 women

The possible association between prenatal factors and breast cancer has been discussed for more than a decade. Birth weight has been used commonly as a proxy measure for intrauterine growth. Whereas some previous studies have found support for an association between birth weight and breast cancer, others have been inconclusive or found no association. We investigated the relationship between birth weight and risk of female breast cancer in a cohort of 106,504 Danish women. Birth weights were obtained from school health records on girls born between 1930-1975. Information on breast cancer came from linking the cohort with the Danish Cancer Registry and the Danish Breast Cancer Cooperative Groups Registry. A total of 2,334 cases of primary breast cancer were diagnosed in the cohort during 3,255,549 person-years of follow-up among women with birth weight between 500-6,000 g. Of these, 922 (40%) were diagnosed with primary breast cancer at the age of 50 years or older. A significant association between birth weight and breast cancer was found equivalent to an increase in risk of 9% per 1,000 g increase in birth weight (95% CI 2-17). The increase was observed for all age groups, representing both pre- and post-menopausal women, and irrespective of tumor characteristics. Adjustment for age at first birth and parity did not influence the results. Birth weight is positively associated with risk of breast cancer, indicating that prenatal factors are important in the etiology of breast cancer.     

Time trends in ovarian cancer mortality in Europe (1955-1993): effect of age, birth cohort and period of death

The time trend in ovarian cancer mortality in the European Union over the period 1955-1993, and the age, period-of-death and birth cohort components underlying the trend's evolution were analysed using log-linear Poisson models to quantify risk of dying from ovarian cancer in the different countries and regions of Europe, and ascertain the relative annual trend for each country. Furthermore, age-period-cohort models were fitted for each country in order to ascertain the effect on time trend exerted by the respective age, period-of-death and birth cohort components. Ovarian cancer mortality proved 2.77-fold (95% confidence interval (CI) 2.60-2.95) higher in northern versus southern Europe over the period 1955-1993. Denmark registered the highest adjusted rates, namely, 14.3 per 100000 person-years for the 1989-1993 5-year period, the last studied, with Portugal (4.5 per 100000) and Greece (4.5 per 100000) being the countries with the lowest rates. Spain and Greece, with annual rises of 5.8% (95% CI 5.3-6.3) and 5.1% (95% CI 4.2-6.0) respectively, were the countries that displayed the greatest increase in ovarian cancer mortality. Risk of death associated with the birth cohort effect declined in all northern countries from 1920 to 1930. In the south, Italy and France recorded a decline in risk from 1930. Women in Spain and Greece registered an increase in birth cohort-associated mortality, which became less pronounced after 1930. Ovarian cancer mortality in Europe evinces a south-north distribution pattern. The mortality risk for women cohorts born in northern Europe witnessed a gradual decline from 1920 to 1930. In the southern region: (1) Italy and France display a cohort effect of decreased risk from 1930; and (2) Greece and Spain show a cohort effect of increased risk among the different generations of women, though this became less pronounced from 1930 onwards.     

Age and cohort effects in primary liver cancer

Primary liver cancer incidence data from 30 populations reported in Cancer Incidence in Five Continents were analyzed. After adjustment for time trends, log incidence increases linearly with log age. Liver cancer risk increases more rapidly with age than that of colon cancer, stomach cancer, or lung cancer in non-smokers; it increases less rapidly than that of prostatic cancer or of lung cancer in smokers. Over the past 20 years, most populations have been found to have increasing age-adjusted liver cancer incidence. There is no correlation between change in rates and magnitude of rates. Male rates are higher than female rates and the ratio of the two tends to be higher in high-risk areas.     

Body mass index,physical activity,and television time in relation to mortality risk among endometrial cancer survivors in the NIH-AARP Diet and Health Study cohort

Purpose

Endometrial cancer (EC) survivors are the second largest group of female cancer survivors in the USA, with high prevalence of obesity and physical inactivity. While higher pre-diagnosis body mass index (BMI) has been associated with higher all-cause and disease-specific mortality, pre-diagnosis physical activity has shown mixed evidence of an association with mortality. However, the association between BMI, physical activity, and TV viewing measured after diagnosis and mortality risk among EC survivors is unknown.

Methods

We identified 580 women with EC in the NIH-AARP Diet and Health Study who completed a post-diagnosis questionnaire on BMI, leisure time moderate- to vigorous-intensity physical activity (MVPA), and TV viewing. We used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality.

Results

With a median follow-up time of 7.1 years, we observed 91 total deaths. We found a positive association between BMI (\({\text{HR}}_{{35+\,{\text{ vs.}}\, <25 {\text{kg/m}}^{2} }}\) = 2.14, 95% CI 1.08–4.24 and mortality, and no statistically significant association between TV viewing (HR_{5+ vs. <3 h/day} = 1.46, 95% CI 0.86–2.46) and mortality nor MVPA with mortality (HR_{15+ vs. 0 MET h/week} = 0.72, 95% CI 0.43–1.21) after adjusting for tumor characteristics and demographic factors. Further adjustment for lifestyle and health status attenuated BMI associations (\({\text{HR}}_{{35+\,{\text{ vs.}}\, <25 {\text{kg/m}}^{2} }}\) = 1.47, 95% CI 0.71–3.07), but strengthened the association between TV viewing and mortality (HR_{5+ vs. <3 h/day} = 2.28, 95% CI 1.05–4.95).

Conclusions

Our results suggest that higher post-diagnosis BMI and TV viewing may be associated with higher mortality risk among EC patients, but that there may be complicated interrelationships between lifestyle factors of BMI, PA, and TV viewing and the mediating role of health status that need to be clarified.

     

Testicular cancer: marked birth cohort effects on incidence and a decline in mortality in southern Netherlands since 1970

The aim of our study was to interpret the changing incidence, and to describe the mortality of patients with testicular cancer in the south of the Netherlands between 1970 and 2004. On the basis of data from the Eindhoven Cancer Registry and Statistics Netherlands, 5-year moving average standardised incidence and mortality rates were calculated. An age-period-cohort (APC) Poisson regression analysis was performed to disentangle time and birth cohort effects on incidence. The incidence rate remained stable for all ages at about 3 per 100,000 person-years until 1989 but increased annually thereafter by 4% to 6 in 2004. This increase can almost completely be attributed to an increase in localised tumours. The largest increase was found for seminoma testicular cancer (TC) patients aged 35-39 and non-seminoma TC patients aged 20-24 years. Relatively more localised and tumours with lymph node metastases were detected in the later periods. APC analysis showed the best fit with an age-cohort model. An increase in incidence of TC was found for birth cohorts since 1950. The mortality rate dropped from 1.0 per 100,000 person-years in 1970 to 0.3 in 2005, with a steep annual decline of 12% in the period 1979-1986. In conclusion, the increase in incidence of TC was strongly correlated with birth cohorts since 1945. The increase in incidence is possibly caused by in utero or early life exposure to a yet unknown risk factor. There was a steep decline in mortality in the period 1979-1986.