Significant Birth Cohort Effect Research Articles

Advances in statistical methods for cancer surveillance research: an age-period-cohort perspective.

Analysis of Lexis diagrams (population-based cancer incidence and mortality rates indexed by age group and calendar period) requires specialized statistical methods. However, existing methods have limitations that can now be overcome using new approaches. We assembled a "toolbox" of novel methods to identify trends and patterns by age group, calendar period, and birth cohort. We evaluated operating characteristics across 152 cancer incidence Lexis diagrams compiled from United States (US) Surveillance, Epidemiology and End Results Program data for 21 leading cancers in men and women in four race and ethnicity groups (the "cancer incidence panel"). Nonparametric singular values adaptive kernel filtration (SIFT) decreased the estimated root mean squared error by 90% across the cancer incidence panel. A novel method for semi-parametric age-period-cohort analysis (SAGE) provided optimally smoothed estimates of age-period-cohort (APC) estimable functions and stabilized estimates of lack-of-fit (LOF). SAGE identified statistically significant birth cohort effects across the entire cancer panel; LOF had little impact. As illustrated for colon cancer, newly developed methods for comparative age-period-cohort analysis can elucidate cancer heterogeneity that would otherwise be difficult or impossible to discern using standard methods. Cancer surveillance researchers can now identify fine-scale temporal signals with unprecedented accuracy and elucidate cancer heterogeneity with unprecedented specificity. Birth cohort effects are ubiquitous modulators of cancer incidence in the US. The novel methods described here can advance cancer surveillance research.

An age-period-cohort analysis of trends in psychedelic and ecstasy use in the Australian population

AimTo test the age, cohort, and period effect on past-year use trends in psychedelic drugs and ecstasy. MethodData were from a repeated cross-sectional nationally representative household survey in Australia conducted every three years between 2001 and 2019. An age-period-cohort model was used to test the effect of age, birth cohort, and period on past year psychedelic and ecstasy use. Participants were between 18 and 80 years old at the time of the survey. The total sample size was 149,296 (Mean age = 45.8; 56% female). Past-year use of psychedelics and ecstasy were the key outcome variables. There were six birth cohorts that were derived in each survey: 1936–50, 1951–60, 1961–70, 1971–80, 1981–90, and 1991–2001. There were seven periods that coincided with survey years: 2001, 2004, 2007, 2010, 2013, 2016 and 2019. Age was treated as continuous. ResultsPast-year use of both psychedelics and ecstasy decreased with age, b = −0.87, 95% CI [−1.14, −0.61] and b = −0.84, 95% CI [−1.08, −0.60]. For ecstasy, while there was significant variation across periods (p < .001), there was no obvious trend. There was a significant birth cohort effect (p < .001), with prevalence increasing from the 1936–50 cohort, peaking in the 1971–80 cohort and then decreasing in the 1991–2001 cohort. For psychedelics, there was significant variation across periods (p < .001) with an upward trend. There was a significant birth cohort effect (p < .001), with prevalence increasing from the 1936–50 cohort to similarly high prevalence for the three most recent cohorts (1971–80, 1981–90, 1991–2001). ConclusionThere were strong cohort and period effects in trends in the use of psychedelic and ecstasy.

Disparities of birth cohort effects on pancreatic cancer incidence between the United States and urban China

BackgroundPancreatic cancer has been associated with lifestyle factors, but few comparative studies were conducted among countries of different culture and lifestyle habits. This study compared the trends of pancreatic cancer incidence and birth cohort effects in the United States and urban China and explored the potential discrepancies of risk patterns.Materials and methodsAge-standardized incidence rates (ASIRs) were calculated using data from national or regional cancer registries of the United States and two large cities of China (Shanghai, Hong Kong). The temporal trends of incidence were assessed by joinpoint regression. The effects of birth cohort and calendar period were identified through age–period–cohort modeling.ResultsThe ASIR in the United States from 1976 to 2015 was 8.26/100 000, which was higher than that in Hong Kong (4.29/100 000) and Shanghai of China (6.63/100 000). Shanghai had lower incidence (4.41/100 000) in 1976-1980 but increased annually by 1.38% in males and 1.67% in females, with a sharper upward trend than the United States and Hong Kong. Males had higher risks than females, with a male-to-female ratio of 1.34, 1.44, and 1.37 in the United States, Hong Kong, and Shanghai, respectively. A significant and prominent increase in incidence rate was observed among successive generations in China particularly for Shanghai, but such a pattern was not apparent in the United States.ConclusionsThe differences in pancreatic cancer incidence by sex may be multi-factorial involving known risk factors like tobacco smoking and alcohol consumption. The significant birth cohort effects among recent and early generations in the Shanghai population were in line with a society in socioeconomic transition and adoption of Western lifestyle mainly including consumption of calorie-rich foods and physical inactivity. Differences in these risk patterns will have implications on health care efforts and policies for cancer control.

Past trends in obesity-attributable mortality in eight European countries: an application of age\u2013period\u2013cohort analysis

ObjectivesTo assess age, period, and birth cohort effects and patterns of obesity-attributable mortality in Czech Republic, Finland, France, Germany, Hungary, Italy, Poland, and the UK (UK).MethodsWe obtained obesity prevalence and all-cause mortality data by age (20–79), sex and country for 1990–2012. We applied Clayton and Schifflers’ age–period–cohort approach to obesity-attributable mortality rates (OAMRs).ResultsBetween 1990 and 2012, obesity prevalence increased and age-standardised OAMRs declined, although not uniformly. The nonlinear birth cohort effects contributed significantly (p < 0.01) to obesity-attributable mortality trends in all populations, except in Czech Republic, Finland, and among German women, and Polish men. Their contribution was greater than 25% in UK and among French women, and larger than that of the nonlinear period effects. In the UK, mortality rate ratios (MRRs) increased among the cohorts born after 1950. In other populations with significant birth cohort effects, MRRs increased among the 1935–1960 cohorts and decreased thereafter.ConclusionsGiven its potential effects on obesity-attributable mortality, the cohort dimension should not be ignored and calls for interventions early in life next to actions targeting broader societal changes.

Incidence of MS has increased markedly over six decades in Denmark particularly with late onset and in women.

To describe the pattern of development of incidence of multiple sclerosis (MS) over 60 years in Denmark with age-period-cohort analyses and seasonality of birth. Data on virtually all patients with onset of MS have since 1950 been prospectively recorded and kept in the Danish Multiple Sclerosis Registry with multiple sources of notification. Annualized incidence rates per 100,000 were directly standardized to the European Standard Population. We have registered 19,536 cases with clinical onset of confirmed MS in Denmark from 1950 to 2009. From the 1950-1959 to the 2000-2009 onset period, incidence more than doubled in women, with an increase from 5.91 (95% confidence interval [CI]: 5.60-6.24) to 12.33 (95% CI: 11.91-12.75) per 100,000 per year compared with a modest 24% increase in men from 4.52 (95% CI: 4.24-4.81) to 6.08 (95% CI: 5.79-6.38). With age at onset of 50 years and older, incidence increased with a factor 4.30 in women and 2.72 in men. The female/male sex ratio increased over time and with year of birth. Age-period-cohort analysis revealed a significant birth cohort effect in addition to the age and period effect. We found no statistically significant seasonality of births. The incidence of MS has doubled in women, most pronounced with late onset, and has only modestly increased in men. Lifestyle changes in the female population that could include fewer childbirths, increased occurrence of obesity, and increased cigarette consumption may have a role.

Ischemic Stroke Rate Increases in Young Adults: Evidence for a Generational Effect?

BackgroundThe incidence rates of ischemic stroke and ST‐segment elevation myocardial infarction (STEMI) have decreased significantly in the United States since 1950. However, there is evidence of flattening of this trend or increasing rates for stroke in patients younger than 50 years. The objective of this study was to examine the changes in incidence rates of stroke and STEMI using an age‐period‐cohort model with statewide data from New Jersey.Methods and ResultsWe obtained stroke and STEMI data for the years 1995–2014 from the Myocardial Infarction Data Acquisition System, a database of hospital discharges in New Jersey. Rates by age for the time periods 1994–1999, 2000–2004, 2005–2009, and 2010–2014 were obtained using census estimates as denominators for each age group and period. The rate of stroke more than doubled in patients aged 35 to 39 years from 1995–1999 to 2010–2014 (rate ratio [RR], 2.47; 95% CI, 2.07–2.96 [P<0.0001]). We also found increased rates of stroke in those aged 40 to 44, 45 to 49, and 50 to 54 years. Strokes rates in those older than 55 years decreased during these time periods. Those born from 1945–1954 had lower age‐adjusted rates of stroke than those born both in the prior 20 years and in the following 20 years. STEMI rates, in contrast, decreased in all age groups and in each successive birth cohort.ConclusionsThere appears to be a significant birth cohort effect in the risk of stroke, where patients born from 1945–1954 have lower age‐adjusted rates of stroke compared with those born in earlier and later years.

Effects of socioeconomic status on physical and mental health of hemodialysis patients in Japan: differences by age, period, and cohort.

Study purposeWhether or not socioeconomic status (SES)-related differences in the health of hemodialysis patients differ by age, period, and birth cohort remains unclear. We examined whether SES-related gaps in physical and mental health change with age, period, and birth cohort for hemodialysis patients.MethodsData were obtained from repeated cross-sectional surveys conducted in 1996, 2001, 2006, and 2011, with members of a national patients’ association as participants. We used raking adjustment to create a database which had similar characteristics to the total sample of dialysis patients in Japan. SES was assessed using family size-adjusted income levels. We divided patients into three groups based on their income levels: below the first quartile, over the second quartile and under the third quartile, and over the fourth quartile. We used the number of dialysis complications as a physical health indicator and depressive symptoms as a mental health indicator. We used a cross-classified random-effects model that estimated fixed effects of age categories and period as level-1 factors, and random effects of birth cohort as level-2 factors.ResultsRelative risk of dialysis complications in respondents below the first quartile compared with ones over the fourth quartile was reduced in age categories >60 years. Mean differences in depressive symptoms between respondents below the first quartile and ones over the fourth quartile peaked in the 50- to 59-year-old age group, and were reduced in age groups >60 years. In addition, mean differences varied across periods, widening from 1996 to 2006. There were no significant birth cohort effects on income differences for dialysis complications or depressive symptoms.ConclusionThe number of dialysis complications and depressive symptoms in dialysis patients were affected by income differences, and the degree of these differences changed with age category and period.

Recent trends in cerebral palsy survival. Part I: period and cohort effects.

To determine whether the trend of improved survival among individuals with cerebral palsy (CP) in California during the 1980s and 1990s has continued during the most recent decade. In an observational cohort study we evaluated individuals with CP, aged 4 years and older, who were clients of the California Department of Developmental Services. Medical diagnoses, functional disabilities, and special health care requirements were assessed with Client Development Evaluation Reports made between 1983 and 2010. Trends in birth cohort survival were analyzed with Kaplan-Meier curves and Cox regression. Calendar year period effects were analyzed with Poisson regression. A total of 51,923 persons with CP (28,789 males [55%], 23,134 females [45%]; mean age 14y 11mo, SD 14y 1mo, range 4y 0mo to 96y 10mo) collectively contributed 662,268 years of follow-up. There were 7690 deaths for an overall mortality rate of 11.6 per 1000 persons per year. No significant birth cohort effects on survival were observed in 4-year-olds who had no severe disabilities. By contrast, children who did not lift their heads in prone position who were born in more recent years had significantly lower mortality rates (Cox hazard ratio 0.971, p<0.001) than those with comparable disabilities born earlier. With regard to calendar year period effects, we found that age-, sex-, and disability-specific mortality rates declined by 1.5% (95% CI 0.9-2.1) year-over-year from 1983 to 2010. The estimate increased to 2.5% (95% CI 1.9-3.1) per year when we additionally controlled for tube-feeding status. Mortality rates in tube fed adolescents and adults, ages 15 to 59 years, declined by 0.9% (95% CI, 0.4-1.4) per year. No improvement was observed for adolescents or adults who fed orally or for those over age 60. In fact, the ratio of age-specific mortality rates for these latter groups to those in the general population, increased by 1.7% (95% CI 1.3-2.0) per year during the study period. The trend toward improved survival has continued throughout the most recent decade. Declines in CP childhood mortality are comparable to the improvements observed in the United States general population (i.e. the mortality ratio in childhood has remained roughly constant over the last three decades). In contrast, the mortality ratio for most adolescents and adults with CP, relative to the general population, has increased.

Trends in hip fracture rates in Canada: An age-period-cohort analysis

Age-standardized rates of hip fracture in Canada declined during the period 1985 to 2005. We investigated whether this incidence pattern is explained by period effects, cohort effects, or both. All hospitalizations during the study period with primary diagnosis of hip fracture were identified. Age- and sex-specific hip fracture rates were calculated for nineteen 5-year age groups and four 5-year calendar periods, resulting in 20 birth cohorts. The effect of age, calendar period, and birth cohort on hip fracture rates was assessed using age-period-cohort models as proposed by Clayton and Schiffers. From 1985 to 2005, a total of 570,872 hospitalizations for hip fracture were identified. Age-standardized rates for hip fracture have progressively declined for females and males. The annual linear decrease in rates per 5-year period were 12% for females and 7% for males (both p < 0.0001). Significant birth cohort effects were also observed for both sexes (p < 0.0001). Cohorts born before 1950 had a higher risk of hip fracture, whereas those born after 1954 had a lower risk. After adjusting for age and constant annual linear change (drift term common to both period and cohort effects), we observed a significant nonlinear birth cohort effect for males (p = 0.0126) but not for females (p = 0.9960). In contrast, the nonlinear period effect, after adjustment for age and drift term, was significant for females (p = 0.0373) but not for males (p = 0.2515). For males, we observed no additional nonlinear period effect after adjusting for age and birth cohort, whereas for females, we observed no additional nonlinear birth cohort effect after adjusting for age and period. Although hip fracture rates decreased in both sexes, different factors may explain these changes. In addition to the constant annual linear decrease, nonlinear birth cohort effects were identified for males, and calendar period effects were identified for females as possible explanations.

Changes in serum levels of biochemical markers of bone turnover during 10 years among Japanese men and women: associated factors and birth-cohort effect. The Taiji Study

We aimed to clarify changes in biochemical markers of bone turnover (BTMs) over 10 years, associations with changes in bone mineral density (BMD), and birth-cohort effects in a Japanese community. We randomly selected 400 individuals (age, 40-79 years; 50 of each gender and age stratum) from a list of registered residents in 1993. We measured BMD of the spine and hip, and serum concentrations of total osteocalcin (OC), beta-C-terminal cross-linking telopeptide of type I collagen (beta-CTX), and N-terminal cross-linking telopeptide of type I collagen (NTX), in 1993 and 2003. Of the 400 subjects, 322 (153 men, 169 women) completed the 10-year follow-up. Mean change rates (standard deviation) for serum total OC, beta-CTX, and NTX over 10 years were -1.00 (3.74)%/year, 5.10 (22.48)%/year, and 0.40 (3.41)%/year, respectively, in men, and 0.02 (5.32)%/year, 5.53 (14.54)%/year, and 0.62 (3.26)%/year, respectively, in women. Change rates of BTMs were higher for women in their forties than for women in their fifties to seventies (P < 0.05), and higher in the menstrual transition group than in pre- and postmenopausal groups (P < 0.001). Changes in levels of BTMs over 10 years in women were significantly associated with change rates of BMDs at L2-L4 and total hip after adjusting for potential confounders. A significant birth-cohort effect was observed among women in their fifties. We concluded that change rates of BTMs during the 10 years were influenced by menstrual transition, age, and sex and associated with bone loss at L2-L4 and total hip.

Trends in testicular germ cell cancer incidence in Australia

Although increasing incidence of testicular germ cell cancer has been reported in many developed nations, national estimates for Australia, with histological differentiation, are not currently available. Using data from all state and territory population-based cancer registries in Australia, this paper reports on incidence trends for seminomas and non-seminomas in Australia between 1982 and 2004 using Joinpoint and Age-Period-Cohort models. Of the 10,528 testicular germ cell cancers diagnosed during this period, 6086 (58%) were seminomas. Incidence rates have increased (2.6% per year) in Australia since 1982, with the effect stronger among seminomas (3.4% per year) rather than non-seminomas (1.4% per year). There was a strong age effect evident for both subtypes, peaking in the 25-29 year age group for non-seminomas and the 30-34 year age group for seminomas. Non-seminoma rates reflected a significant birth cohort effect, following a U-shaped pattern with the lowest risk among the 1,945 birth cohort. The differential trends observed for Australia for seminomas and non-seminomas are consistent with those reported for the United States, but slightly different to those reported for Europe. The trends may be at least partly due to changes over time in the prevalence of etiologic or protective factors around the time of birth.

Ovarian cancer in Western Australia (1982–98): incidence, mortality and survival

Objectives: To investigate the trends in incidence and mortality and estimate survival for women diagnosed with ovarian cancer in Western Australia.Case selection and methods: There were 1,336 women diagnosed with ovarian cancer in 1982–98. Age‐standardised rates were calculated by the direct method. Age‐period and age‐cohort models were analysed by Poisson regression. The Kaplan‐Meier method was used to estimate survival and Cox proportional hazards regression evaluated the relative risk of dying.Results: Trends in age‐adjusted incidence and mortality rates showed little changed over the three time periods of diagnosis. A significant birth cohort effect showed a peak in the risk in the 1924 (mid‐year) cohort followed by a general decrease in both incidence and mortality risk. Survival at five years was 34% (95% CI 31.3–36.5) overall, but was only 27% (95% CI 17.4–36.7) among women with stage III and IV disease. Aboriginal women showed a risk of dying twice that of non‐Aboriginal women.Conclusions: The birth cohort analysis of ovarian cancer proved better at explaining disease trends than was time period of diagnosis. Survival continues to be poor, but Aboriginal women and those with serous and unspecified adenocarcinoma tumours fair much worse.Implications: As the leading cause of death from a gynaecological malignancy, ovarian cancer is of public health importance. Historical trends in birth rates and the use of oral contraceptives help to explain at least some of the observed birth cohort trends in this study. In the long term, an effective diagnostic technique needs to be developed or this disease will continue to be diagnosed at an advanced stage when treatment options for cure are limited.

Increased risk of childhood type 1 diabetes in children born after 1985.

The incidence rate of childhood type 1 diabetes is thought to be increasing; however, Danish studies have not confirmed this. Using a national diabetes register initiated in 1996 and two previous regional incidence studies, we studied the age-specific incidence of type 1 diabetes over 30 years. Here, we describe the incidence rates of type 1 diabetes in Danish children from 1996 to 2000 and evaluate trends in age-specific incidence rates from 1970 to 2000. A nationwide registration of all newly diagnosed cases of type 1 diabetes among children under the age of 15 years was established in Denmark in 1996. Incidence rates of type 1 diabetes in Denmark were obtained from this register. Age-specific incidence rates were compared with data collected from 1970 to 1976 and from 1980 to 1984, both population-based studies using existing national routine registration of hospitalizations within the survey areas. Population data were obtained from Statistics Denmark. During the study period, 1,421 Danish children developed type 1 diabetes before the age of 15 years. The incidence rates by age-groups were: 12.7, 19.4, and 26.3 for the 0-4, 5-9, and 10-14 years age-groups, respectively, and 19.5 for the 0-14 years age-group per 100,000 in the period 1996-2000. An age-period-cohort analysis showed a modest drift effect (yearly increase) of 1.2% (0.7-1.8) from 1970 to 2000, and a significant birth cohort effect with an increased risk for children born after 1985 was observed. The incidence rate of type 1 diabetes is rising in children living in Denmark. The steep increase in the youngest age-group was explained by the increased risk for cohorts born at the beginning of the 1980s.

Changes in women's assertiveness in response to status and roles: A cross-temporal meta-analysis, 1931–1993.

Across two meta-analyses, American women's assertiveness rose and fell with their social status from 1931 to 1993. College women and high school girls' self-reports on assertiveness and dominance scales increased from 1931 to 1945, decreased from 1946 to 1967, and increased from 1968 to 1993, explaining about 14% of the variance in the trait. Women's scores have increased enough that many recent samples show no sex differences in assertiveness. Correlations with social indicators (e.g., women's educational attainment, women's median age at first marriage) confirm that women's assertiveness varies with their status and roles. Social change is thus internalized in the form of a personality trait. Men's scores do not demonstrate a significant birth cohort effect overall. The results suggest that the changing sociocultural environment for women affected their personalities, most likely beginning in childhood.

Biologically Based Analysis of the Data for the Colorado Uranium Miners Cohort: Age, Dose and Dose-Rate Effects

This study is a comprehensive analysis of the latest follow-up of the Colorado uranium miners cohort using the two-stage clonal expansion model with particular emphasis on effects related to age and exposure. The model provides a framework in which the hazard function for lung cancer mortality incorporates detailed information on exposure to radon and radon progeny from hard rock and uranium mining together with information on cigarette smoking. Even though the effect of smoking on lung cancer risk is explicitly modeled, a significant birth cohort effect is found which shows a linear increase in the baseline lung cancer risk with birth year of the miners in the cohort. The analysis based on the two-stage clonal expansion model suggests that exposure to radon affects both the rate of initiation of intermediate cells in the pathway to cancer and the rate of proliferation of intermediate cells. However, in contrast to the promotional effect of radon, which is highly significant, the effect of radon on the rate of initiation is found to be not significant. The model is also used to study the inverse dose-rate effect. This effect is evident for radon exposures typical for mines but is predicted to be attenuated, and for longer exposures even reversed, for the more protracted and lower radon exposures in homes. The model also predicts the drop in risk with time after exposure ceases. For residential exposures, lung cancer risks are compared with the estimates from the BEIR VI report. While the risk estimates are in agreement with those derived from residential studies, they are about two- to fourfold lower than those reported in the BEIR VI report.

Decline in the incidence of schizophrenia in Finnish cohorts born from 1954 to 1965.

The declining incidence of schizophrenia observed in several countries is believed by many to merely reflect methodological problems in the studies performed. We report the first nationwide historical cohort study of changes in the incidence of schizophrenia, in which many of the previous methodological problems were overcome. We used the Finnish Population Register to identify everyone born in Finland from 1954 to 1965. These persons were followed up from their 16th to their 26th birthdays, and all cases of schizophrenia (International Classification of Diseases, Eighth Revision and International Classification of Diseases, Ninth Revision code 295) that emerged were identified from the National Hospital Discharge Register, the Pension Register, and the Free Medicine Register. Persons for whom an age of onset could be defined were included in the analyses (n = 5645). We used the Poisson regression model to estimate the effects of age, sex, birth cohort, period of diagnosis, and season of birth on the incidence of schizophrenia. The relative importance of cohort and period were assessed using an age-period-cohort model. The incidence declined significantly in each successive cohort, from 0.79 to 0.53 per 1000 among males and from 0.58 to 0.41 per 1000 among females. The effects of cohort and period on the change were both significant. The incidence of schizophrenia has declined in Finland. This was partly caused by confounding factors, as reflected in the significant period effect. The significant birth cohort effect suggests that the intensity or frequency of one or more risk factors for schizophrenia has decreased.

Colorectal carcinoma among ethnic Chinese in Singapore: trends in incidence rate by anatomic subsite from 1968 to 1992.

Recent epidemiologic studies have suggested that the anatomic distribution of colorectal carcinoma may have undergone a distal to proximal shift over several decades, which has been attributed variously to environmental and genetic factors as well as preventive intervention. Trends in subsite distribution and the incidence rate of colorectal carcinoma among Chinese in Singapore between 1968 and 1992 were explored using data from the Singapore Cancer Registry (n = 10,489). Age-standardized incidence rates were computed and compared further using age-period-cohort models by subsite and gender. The proportion of lesions in the distal colon was found to have increased from 23.2% to 24.4% whereas that for the proximal colon and rectum were fairly consistent over the past 25 years. Our results also showed that age-standardized rates have doubled in proximal lesions (2-3% annually) and more than doubled in distal lesions (3-4% annually) whereas rates in rectal carcinoma have shown a slight increase or stability over time. The patterns of change in all subsite tumors could be attributed to a significant birth cohort effect. The results of the current study suggest that incidence rates have increased rapidly with no distal to proximal shift observed among ethnic Chinese in Singapore over the past 25 years. The pattern of change differs from findings reported in high incidence countries such as the U. S. and parts of Europe, suggesting that the preventive intervention and early diagnostic capabilities that may have played an important role in these countries have had less effect in Asia. The rapid overall increase in the incidence rate of colon carcinoma supports the role of dietary and other environmental factors as possible risk factors.

Trends in oral cancer by subsite in New Zealand.

A significant increase in incidence rates for all subsites of oral cancer in men and all but cancer of the salivary glands in women has occurred in New Zealand over the past 35 years. However, only male mortality rates of cancers of the nasopharynx and pharynx (excluding the nasopharynx) have significantly increased during this time period. Significant birth-cohort effects existed in the trends in incidence and mortality for cancers of the tongue, mouth, pharynx (excluding the nasopharynx), and nasopharynx among men. For cancers of the mouth and pharynx (excluding the nasopharynx) an increased risk for men born 1912-1932 existed, while an increased risk of cancer of the tongue occurred for men born 1922 onwards. For nasopharyngeal cancer, men born around 1912 and those born from about 1932 onwards were found to have an increased risk. For women, no consistent trends by birth-cohort were found for any oral subsite of cancer.