Do socio-economic gradients in smoking emerge differently across time by gender? Implications for the tobacco epidemic from a pregnancy cohort in California, USA.
ABSTRACT: Understanding current patterns of population smoking by socioeconomic position (SEP) can be substantially enhanced by research that follows birth cohorts over long periods of time, yet such data in the US are rare. Information from birth cohorts followed during critical time periods when the health consequences of smoking became widely known can inform the ways in which current smoking prevalence has been shaped by the historical processes that preceded it. The present study utilizes data from a substudy of the Child Health and Development Study pregnancy cohort (N = 1612). Women were queried about smoking status in 1959-1962, 1971-1972 and 1977-1980. Women were divided into three cohorts based on date of birth. Offspring represented another birth cohort assessed for smoking in 1977-1980. Results indicated that the overall prevalence of smoking exhibited cohort-specific patterns that persisted across time. Notably, the youngest maternal cohort (born 1937-1946) had high smoking prevalence throughout and showed no appreciable decrease (44.7%, 41.4%, 40.1% for 1959-1962, 1971-1972, and 1977-1980). Results also indicated that the relation of smoking to SEP exhibited cohort-specific patterns over time. Among the oldest birth cohort (born 1914-1930), no inverse relation of SEP to smoking was observed at any time; in contrast, an inverse relation emerged by 1959-1962 among the youngest cohort of mothers. Among the adolescent offspring, there was a strong SEP gradient (OR = 2.0, 95% CI = 1.4-3.0) that was stronger than in any maternal birth cohort at any assessment (? = 0.40, SE = 0.1, p<0.01). We conclude that SEP gradients in smoking emerge across birth cohorts rather than time alone, with increasingly strong gradients across time especially among younger cohorts.
Project description:The aim of our study was to quantify sex-specific patterns of smoking prevalence and initiation in 10-year birth cohorts from 1910 to 1989 in Australia. We combined individual data of 385,810 participants from 33 cross-sectional surveys conducted between 1962 and 2018. We found that age-specific smoking prevalence varied considerably between men and women within birth cohorts born before 1960. The largest difference was observed in the earliest cohort (1910-1919), with up to 37.7% point greater proportion of current smokers in men than in women. In subsequent cohorts, the proportion decreased among men, but increased among women, until there was no more than 7.4% point difference in the 1960-69 birth cohort. In the 1970-79 and 1980-89 cohorts, smoking among men marginally increased, but the proportion was at most ~11.0% points higher than women. Our analysis of initiation indicated that many women born before the 1930s who smoked commenced smoking after age 25 years (e.g., ~27% born in 1910-19); compared to at most 8% of men in any birth cohort. The earliest birth cohort (1910-1919) had the greatest difference in age at initiation between sexes; 26.6 years in women versus 19.0 in men. In later cohorts, male and female smokers initiated increasingly earlier, converging in the 1960-69 cohort (17.6 and 17.8 years, respectively). While 22.9% of men and 8.4% of women initiated smoking aged < = 15 in the 1910-1919 cohort, in the latest cohort (1980-89) the reverse was true (21.4% and 28.8% for men and women, respectively). Marked differences in smoking prevalence and age at initiation existed between birth cohorts of Australian men and women born before 1960; after this, sex-specific trends in prevalence and initiation were similar. Understanding these patterns may inform the evaluation of tobacco control policies and the targeting of potential interventions for exposed populations such as lung cancer screening.
Project description:Evidence remains unclear on how intergenerational social mobility is associated with body mass index (BMI) and its long-term changes. Our study identified BMI trajectories from middle to older age by intergenerational social mobility groups and stratified the analyses by gender and two birth cohorts (birth years 1940?1947 and 1950-1962). We used questionnaire-based cohort data that consists of four survey phases: 2000-2002, 2007, 2012, and 2017. In Phase 1, participants were 40-60-year-old employees of the City of Helsinki, Finland. Our analytical sample consisted of 6,971 women and 1,752 men. Intergenerational social mobility was constructed based on self-reported parental and own education-both divided into high and low-yielding four groups: stable high socioeconomic position (SEP) (high-high), upward social mobility (low-high), downward social mobility (high-low), and stable low SEP (low-low). BMI was calculated from self-reported height and weight from all four phases. Using mixed-effects linear regression, we found increasing BMI trajectories in all four social mobility groups until the age of 65. Women and men with stable high SEP had lower BMI trajectories compared to those with stable low SEP. In the younger birth cohort, women with upward social mobility had a lower BMI trajectory than women with stable low SEP. Additionally, women and men with downward social mobility had higher BMI trajectories than those with stable high SEP. In the older birth cohort, however, the BMI trajectories of upward and downward social mobility groups were somewhat similar and settled between the BMI trajectories of stable high and stable low SEP groups. Our results indicate that the associations between intergenerational social mobility and BMI may depend on gender and birth cohort. Nevertheless, to reduce socioeconomic inequalities in unhealthy weight gain, obesity prevention actions that focus on people who are likely to remain in low SEP might be worthwhile.
Project description:In England, cervical cancer is the second most common cancer in women aged under 35 years. Overall incidence of cervical cancer has decreased since the introduction of the national screening programme in 1988 but recent trends of incidence in young women have not been studied in detail.Information on 71,511 incident cases of cervical cancer in England, 1982-2006, in 20-79-year-olds was extracted from a national cancer registration database. Changes in incidence were analysed by age group, time period and birth cohort. Poisson regression was used to estimate annual percentage change (APC).Overall incidence, during 1982-2006, fell significantly from 213 to 112 per million person years. However, in 20-29-year-olds, after an initial fall, incidence increased significantly during 1992-2006, (APC 2.16). In 30-39-year-olds incidence stabilised during the latter part of the study period. The pattern was most marked in the North East, Yorkshire and the Humber and East Midlands regions. Birth cohorts that were initially called for screening between 60-64 and 35-39 years of age show an incidence peak soon after the age of presumed first screen, whereas younger birth cohorts show a peak at about 35 years of age. Incidence in the 1977-1981 birth cohort has increased relative to that among women born between 1962 and 1976.These results have implications for cervical screening, human papilloma virus vaccination and other public health interventions targeting young people.
Project description:OBJECTIVES:To develop a model to predict future socioeconomic inequalities in body mass index (BMI) and obesity. DESIGN:Microsimulation modelling using BMI data from adult participants of Australian Health Surveys, and published data on the relative risk of mortality in relation to BMI and socioeconomic position (SEP), based on education. SETTING:Australia. PARTICIPANTS:74?329 adults, aged 20 and over from Australian Health Surveys, 1995-2015. PRIMARY AND SECONDARY OUTCOME MEASURES:The primary outcomes were BMI trajectories and obesity prevalence by SEP for four birth cohorts, born 10 years apart, centred on 1940, 1950, 1960 and 1970. RESULTS:Simulations projected persistent or widening socioeconomic inequality in BMI and obesity over the adult life course, for all birth cohorts. Recent birth cohorts were predicted to have greater socioeconomic inequality by middle age, compared with earlier cohorts. For example, among men, there was no inequality in obesity prevalence at age 60 for the 1940 birth cohort (low SEP 25% (95% CI 17% to 34%); high SEP 26% (95% CI 19% to 34%)), yet for the 1970 birth cohort, obesity prevalence was projected to be 51% (95% CI 43% to 58%) and 41% (95% CI 36% to 46%) for the low and high SEP groups, respectively. Notably, for more recent birth cohorts, the model predicted the greatest socioeconomic inequality in severe obesity (BMI >35?kg/m2) at age 60. CONCLUSIONS:Lower SEP groups and more recent birth cohorts are at higher risk of obesity and severe obesity, and its consequences in middle age. Prevention efforts should focus on these vulnerable population groups in order to avoid future disparities in health outcomes. The model provides a framework for further research to investigate which interventions will be most effective in narrowing the gap in socioeconomic disparities in obesity in adulthood.
Project description:BACKGROUND AND AIMS:The long-term population health impact of nicotine vaping products (NVPs) use among smokers is unknown, and subject to a range of plausible assumptions about the use and health consequences of NVPs. While NVPs use may substitute for cigarette smoking and thereby aid in quitting cigarette use, it is also possible that smokers who would have otherwise quit would instead delay quitting cigarettes. We aimed to develop a cohort-specific simulation model of the impact of NVPs on smoking cessation by adult smokers and resulting premature deaths (PD) and life years lost (LYL). DESIGN:A cohort-specific simulation model of the impact of NVPs on smoking cessation by adult smokers and resulting premature deaths (PD) and life years lost (LYL) was developed by gender for two birth cohorts, aged 30 and 50 years in 2012. Extensive sensitivity analyses were conducted. SETTING:United States. PARTICIPANTS:Smokers in two birth cohorts, aged 30 and 50 years in 2012. MEASUREMENTS:Data were from the 1965-2012 National Health Interview Surveys and the 2014/15 Tobacco Use Supplement of the Current Population Survey. The model incorporated a range of plausible assumptions from published literature about transition rates from regular smoking to exclusive NVP and dual use, from dual use to exclusive NVP use and from exclusive NVP use to no use. FINDINGS:Compared with the no-NVP scenario, the male (female) model projected 17.8% (19.3%) fewer PDs and 22.9% (26.6%) fewer LYL for the 1982 cohort and 5.4% (7.3%) fewer PDs and 7.9% (11.4%) fewer LYL for the 1962 cohort. These gains were sensitive to NVP use over time, age of initial NVP use, transitions from smoking to dual, exclusive NVP and no use and relative NVP mortality risks. CONCLUSIONS:Nicotine vaping product (NVP) use in the United States is projected to have a net positive impact on population health over a wide range of plausible levels of NVP use, transitions to dual, exclusive NVP and no use and NVP risks. However, net impact is sensitive to parameter estimates.
Project description:<h4>Objectives</h4>This study systematically compared accumulation, sensitive period, critical period and social mobility models relating life course socioeconomic position (SEP) and adult crystallised cognitive ability, which has not been comprehensively investigated.<h4>Design</h4>Two prospective cohort studies.<h4>Participants</h4>Five thousand three hundred and sixty-two participants in the Medical Research Council National Survey of Health and Development (NSHD) Birth Cohort Study and 10?308 participants in the Whitehall II Occupational Cohort Study.<h4>Measures</h4>Childhood SEP was measured by father's occupational SEP, early adulthood SEP by educational qualifications and adult SEP by own occupational SEP. Each life course model was compared with a saturated model.<h4>Results</h4>Using multiple imputation to account for missing data, the sensitive period model, which contained childhood, early adulthood and adult SEP terms, with different coefficients, provided the best fit for both men and women in the NSHD and Whitehall II cohorts. Early adulthood SEP had the largest coefficient in NSHD women, whereas for NSHD men early adulthood and adult SEP had similar coefficients. In Whitehall II adult SEP had the largest effect size for both men and women.<h4>Conclusions</h4>Sensitive period with all three time periods was the most appropriate life course models for adult crystallised cognitive ability in both cohorts, including an effect of childhood SEP. It is important to directly compare the life course models to determine which is the most appropriate.
Project description:<h4>Background</h4>We examined the associations of maternal age with low birthweight (LBW) and preterm birth in four cohorts from a middle- and a high-income country, where the patterning of maternal age by socio-economic position (SEP) is likely to differ.<h4>Methods</h4>Population-based birth cohort studies were carried out in the city of Pelotas, Brazil in 1982, 1993, and 2004, and in Avon, UK in 1991 [Avon Longitudinal Study of Parents and Children (ALSPAC)]. Adjustment for multiple indicators of SEP were applied.<h4>Results</h4>Low SEP was associated with younger age at childbearing in all cohorts, but the magnitudes of these associations were stronger in ALSPAC. Inverse associations of SEP with LBW and preterm birth were observed in all cohorts. U-shaped associations were observed between maternal age and odds of LBW in all cohorts. After adjustment for SEP, increased odds of LBW for young mothers (<20 years) attenuated to the null but remained or increased for older mothers (? 35 years). Very young (<16 years) maternal age was also associated with both outcomes even after full SEP adjustment. SEP adjusted odds ratio of having a LBW infant in women <16 years and ? 35 years, compared with 25-29 years, were 1.48 [95% confidence interval (CI) 1.00, 2.20] and 1.66 [95% CI 1.36, 2.02], respectively. The corresponding results for preterm birth were 1.80 [95% CI 1.23, 2.64)] and 1.38 [95% CI 1.15, 1.67], respectively.<h4>Conclusion</h4>Confounding by SEP explains much of the excess risk of LBW and preterm among babies born to teenage mothers as a whole, but not for mothers aged <16 or ? 35 years. Given that the proportion of women becoming pregnant at <16 years is smaller than for those ? 35 years, the population burden is greater for older age.
Project description:This study examined the association between famine exposure in early life and the risk of metabolic syndrome (MetS) in adulthood during the 1959-1961 Chinese Famine. Two cross-sectional surveys involving randomly selected Chinese adults aged 35-74 years in the Qingdao area were conducted. A total of 9,588 individuals were grouped into four birth cohorts of unexposed (born between January 1, 1962, and December 31, 1975), fetal-exposed (born between January 1, 1959, and December 31, 1961), childhood-exposed (born between January 1, 1949, and December 31, 1958), and adolescence/adult-exposed cohorts (born between January 1, 1931, and December 31, 1948). We assessed the prevalence rate of MetS in relation to famine exposure according to three definitions of MetS by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III), International Diabetes Federation (IDF), and China Diabetes Society (CDS). According to the CDS criterion, the prevalence rates of MetS were 17.8%, 25.7%, 31.1%, and 45.3% in the unexposed, fetal-, childhood-, and adolescence/adult-exposed cohorts, respectively (P < 0.001). For the CDS criteria, compared with individuals without famine exposure, odds ratios (95% confidence interval) for MetS were 1.36 (1.02-1.81), 1.36 (1.06-1.75), and 1.60 (1.06-2.41) in women and 1.10 (0.79-1.53), 1.07 (0.79-1.42), and 1.21 (0.74-1.99) in men who were exposed in the fetal, childhood, and adolescence/adult periods, respectively, after adjustment for age, study cohorts, residential areas, education levels, income levels, current smoking, and current drinking. The same trend was observed in fetal and childhood exposure for the NCEP-ATP III and IDF definitions, except for a marginal effect in adolescence/adult exposure. Sensitivity analysis revealed that the odds ratios for MetS prevalence for the CDS definition were 1.37 (1.03-1.82), 1.40 (1.09-1.79), and 1.58 (1.04-2.40) among fetal, childhood, and adolescence/adult exposure in rural areas, respectively. The CDS definition is superior to the other definitions for determining the association between famine exposure and MetS with respect to early life. Famine exposure in early life is associated with an increased risk of MetS in later life, especially in women. Early-life malnutrition and later life overnutrition were critical in determining adulthood metabolic disorders.
Project description:<h4>Background</h4>Much of the recent increase in hospital admission rates and mortality associated with hepatitis C in Canada is believed to be because of a higher prevalence of hepatitis C virus infection among those born between 1945 and 1965 (the baby boomer generation). We explored the effects of birth cohort on the rates of and projected trends in hospital admissions associated with hepatitis C.<h4>Methods</h4>The hospital records of 17 344 inpatients with a diagnosis of chronic hepatitis C and liver disease, including liver cancer, were extracted from the Canadian Discharge Abstract Database for April 2004 to March 2011. For each 5-year birth cohort from 1915 to 1984, regression analysis was used to estimate the temporal trends associated with the average age of the cohort during the study period. Future hospital admissions were predicted based on the assumption that past trends would continue.<h4>Results</h4>Hospital admissions associated with hepatitis C and liver disease increased an average of 6.0% (95% confidence interval [CI] 4.4%-7.7%) a year over the study period. As of 2010, hospital admission rates were highest for the 1950-1954 and 1955-1959 birth cohorts, at 17.6 (95% CI 13.2-23.5) and 13.7 (95% CI 10.3-18.2) times the rate for the 1970-1974 birth cohort. The corresponding same-age rate ratios predicted under a status quo scenario were 3.6 (95% CI 2.3-4.9) and 3.4 (95% CI 2.1-4.7). Same-age rate ratios were significantly higher for the four 5-year birth cohorts between 1950 and 1969 compared with other birth cohorts.<h4>Interpretation</h4>Hospital admissions associated with chronic hepatitis C and liver disease were significantly higher for the 1950-1954 and 1955-1959 birth cohorts than for most other birth cohorts. Without further interventions, the disease burden associated with hepatitis C will continue to increase for most birth cohorts, likely peaking after age 70 years. The substantial disease burden emerging in younger birth cohorts should be monitored.
Project description:OBJECTIVE Using a nationally representative sample of the civilian noninstitutionalized U.S. population, we estimated trends in diabetes prevalence across cohorts born 1910-1989 and provide the first estimates of age-specific diabetes incidence using nationally representative, measured data. RESEARCH DESIGN AND METHODS Data were from 40,130 nonpregnant individuals aged 20-79 years who participated in the third National Health and Nutrition Examination Survey (NHANES III), 1988-1994, and the continuous 1999-2010 NHANES. We defined diabetes as HbA1c ?6.5% (48 mmol/mol) or taking diabetes medication. We estimated age-specific diabetes prevalence for the 5-year age-groups 20-24 through 75-79 for cohorts born 1910-1919 through 1980-1989 and calendar periods 1988-1994, 1999-2002, 2003-2006, and 2007-2010. We modeled diabetes prevalence as a function of age, calendar year, and birth cohort, and used our cohort model to estimate age-specific diabetes incidence. RESULTS Age-adjusted diabetes prevalence rose by a factor of 4.9 between the birth cohorts of 1910-1919 and 1980-1989. Diabetes prevalence rose with age within each birth cohort. Models based on birth cohorts show a steeper age pattern of diabetes prevalence than those based on calendar years. Diabetes incidence peaks at 55-64 years of age. CONCLUSIONS Diabetes prevalence has risen across cohorts born through the 20th century. Changes across birth cohorts explain the majority of observed increases in prevalence over time. Incidence peaks between 55 and 64 years of age and then declines at older ages.