Educational inequalities in suicide in the highly volatile economy of Argentina.

PURPOSE: Little is known about how economic fluctuations affect educational inequalities in mortality in low- or middle-income countries. The objective of this study is to analyze the temporal variations in educational differentials in suicide in four Argentinian provinces. METHODS: Data on suicides for ages 25 years and over and three age groups (25-44, 45-64, and 65 +) in four Argentinian provinces during the period 1999-2013 were linked to population data and information on the educational level of the deceased. Regression models were estimated using age, sex, year, province of residence, educational level, and economic character of the year (expansion or recession) as explanatory variables. RESULTS: The educational gap in suicide mortality widened since the expansion following the crisis of 1999-2002, and then only decreased in 2005 and 2011. For ages 45-64, the confidence intervals of the suicide rate overlapped each year, and the suicide rate of the middle-high education population exceeded the suicide rate of the low-education population in 2 recession years, 1999 and 2002. Considering the years of economic expansion or recession as a dichotomous variable, at ages 45-64 differences in suicide rates by educational level disappeared during years of recession, while they were present in years of expansion. CONCLUSION: Suicides rise during economic downturns but these periods could reduce the educational gaps of suicide mortality by increasing the vulnerability of adults of high educational level to changes in the economy.

Household heating associated with disability in activities of daily living among Chinese middle-aged and elderly: a longitudinal study.

BACKGROUND: The health hazards of indoor air pollution are well-established but studies of the health effects due to pollution from heating are rare. This study investigated the association of heating and disability for activities of daily living among Chinese middle-aged and elderly. METHODS: We used two consecutive surveys in a cohort of over 17,000 adults aged 45 or older, who were interviewed first in 2011-2012 and then in 2013. In these surveys, taking advantage of random survey time, we applied a random effects logit regression model that included an interaction between pollution-producing heating fuel and a dummy variable, which measured interview time based on whether or not it was heating season. RESULTS: Exposure to pollution-producing heating fuel was associated with a 39.9% (OR 1.399; 95%CI 1.227-1.594) and 71.0% (OR 1.710; 95%CI 1.523-1.920) increase in the likelihood of disability in activities of daily living (DADL) and disability in instrumental activities of daily living (DIADL), respectively. In heating season between year 2011 and 2013, moving from clean heating energy for heating to pollution-producing fuel was linked with an increase in the likelihoods having DADL and DIADL, with the OR of 2.014 (95%CI 1.126-3.600) and 1.956 (95%CI 1.186-3.226), respectively. However, disability increases due to change from clean energy to pollution-producing heating energy did not appear in advantaged education respondents. CONCLUSIONS: We found that exposure to heating by burning of coal, wood, or crop residue was associated with disability in performing daily living activities. Health policymakers should take indoor pollution due to heating into consideration as it is a major determinant of activities of daily living in elderly people; especially, such policy should focus on elderly people who have disadvantaged education.

Reversal of Upward Trends in Mortality During the Great Recession by Employment Status at Baseline in a National Longitudinal Study.

Because of the healthy worker effect, mortality rates increased in individuals who were employed and those who were unemployed, and decreased in those economically inactive at baseline in reported studies. To determine if such trends continue during economic recessions, we analyzed mortality rates in Spain before and during the Great Recession in these subgroups. We included 21,933,351 individuals who were employed, unemployed, or inactive in November 2001 and aged 30-64 years in each calendar-year of follow-up (2002-2011). Annual age-adjusted mortality rates were calculated in each group. The annual percentage change in mortality rates adjusted for age and educational level in employed and unemployed persons were also calculated for 2002-2007 and 2008-2011. In employed and unemployed men, mortality rates increased until 2007 and then declined, whereas in employed and unemployed women, mortality rates increased and then stabilized during 2008-2011. The mortality rate among inactive men and women decreased throughout the follow-up. In the employed and the unemployed, the annual percentage change was reversed during 2008-2011 compared with 2002-2007 (-1.2 vs. 3.2 in employed men; -0.3 vs. 4.1 in employed women; -0.8 vs. 2.9 in unemployed men; and -0.6 vs. 1.3 in unemployed women). The upward trends in mortality rates among individuals who were employed or unemployed in 2001 were reversed during the Great Recession (2008-2011).

Trends in disease mortality before and during the Great Recession in individuals employed in Spain in 2001.

BACKGROUND: Previous studies on economic recessions and mortality due to cancer and other chronic diseases have yielded inconsistent findings. We investigated the trend in all-disease mortality and mortality due to several specific diseases before and during the Great Recession of 2008 in individuals who were employed in 2001, at the beginning of follow-up. METHODS: We follow in a nationwide longitudinal study over 15 million subjects who had a job in Spain in 2001. The analysed outcomes were mortality at ages 25-64 years due to all diseases, cancer and other chronic diseases. We calculated annual mortality rates from 2003 to 2011, and the annual percentage change (APC) in mortality rates during 2003-07 and 2008-11, as well as the effect size, measured by the APC difference between the two periods. RESULTS: All-disease mortality increased from 2003 to 2007 in both men and women; then, between 2008 and 2011, all-disease mortality decreased in men and reached a plateau in women. In men, the APC in the all-disease mortality rate was 1.6 in 2003-07 and -1.4 in 2008-11 [effect size -3.0, 95% confidence interval (CI) -3.7 to -2.2]; in women it was 2.5 and -0.3 (effect size -2.8, 95% CI -4.2 to -1.3), respectively. Cancer mortality and mortality due to other chronic diseases revealed similar trends. CONCLUSIONS: In the group of individuals with a job in 2001 the Great Recession reversed or stabilized the upward trend in all-disease mortality.

Cardiovascular Risk Factors, Depression, and Alcohol Consumption During Joblessness and During Recessions Among Young Adults in CARDIA.

Research has shown that recessions are associated with lower cardiovascular mortality, but unemployed individuals have a higher risk of cardiovascular disease (CVD) or death. We used data from 8 consecutive examinations (1985-2011) of the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, modeled in fixed-effect panel regressions, to investigate simultaneously the associations of CVD risk factors with the employment status of individuals and the macroeconomic conditions prevalent in the state where the individual lives. We found that unemployed individuals had lower levels of blood pressure, high-density lipoprotein cholesterol, and physical activity, and they had significantly higher depression scores, but they were similar to their counterparts in smoking status, alcohol consumption, low-density lipoprotein cholesterol levels, body mass index, and waist circumference. A 1-percentage-point higher unemployment rate at the state level was associated with lower systolic (-0.41 mm Hg, 95% CI: -0.65, -0.17) and diastolic (-0.19, 95% CI: -0.39, 0.01) blood pressure, higher physical activity levels, higher depressive symptom scores, lower waist circumference, and less smoking. We conclude that levels of CVD risk factors tend to improve during recessions, but mental health tends to deteriorate. Unemployed individuals are significantly more depressed, and they likely have lower levels of physical activity and high-density lipoprotein cholesterol.

Population health and the economy: Mortality and the Great Recession in Europe.

We analyze the evolution of mortality-based health indicators in 27 European countries before and after the start of the Great Recession. We find that in the countries where the crisis has been particularly severe, mortality reductions in 2007-2010 were considerably bigger than in 2004-2007. Panel models adjusted for space-invariant and time-invariant factors show that an increase of 1 percentage point in the national unemployment rate is associated with a reduction of 0.5% (p < .001) in the rate of age-adjusted mortality. The pattern of mortality oscillating procyclically is found for total and sex-specific mortality, cause-specific mortality due to major causes of death, and mortality for ages 30-44 and 75 and over, but not for ages 0-14. Suicides appear increasing when the economy decelerates-countercyclically-but the evidence is weak. Results are robust to using different weights in the regression, applying nonlinear methods for detrending, expanding the sample, and using as business cycle indicator gross domestic product per capita or employment-to-population ratios rather than the unemployment rate. We conclude that in the European experience of the past 20 years, recessions, on average, have beneficial short-term effects on mortality of the adult population.

Individual joblessness, contextual unemployment, and mortality risk.

Longitudinal studies at the level of individuals find that employees who lose their jobs are at increased risk of death. However, analyses of aggregate data find that as unemployment rates increase during recessions, population mortality actually declines. We addressed this paradox by using data from the US Department of Labor and annual survey data (1979-1997) from a nationally representative longitudinal study of individuals-the Panel Study of Income Dynamics. Using proportional hazards (Cox) regression, we analyzed how the hazard of death depended on 1) individual joblessness and 2) state unemployment rates, as indicators of contextual economic conditions. We found that 1) compared with the employed, for the unemployed the hazard of death was increased by an amount equivalent to 10 extra years of age, and 2) each percentage-point increase in the state unemployment rate reduced the mortality hazard in all individuals by an amount equivalent to a reduction of 1 year of age. Our results provide evidence that 1) joblessness strongly and significantly raises the risk of death among those suffering it, and 2) periods of higher unemployment rates, that is, recessions, are associated with a moderate but significant reduction in the risk of death among the entire population.

Economic fluctuations and educational inequalities in premature ischemic heart disease mortality in Argentina.

Although mortality from ischemic heart disease has declined over the past decades in Argentina, ischemic heart disease remains one of the most frequent causes of death. This study aimed to describe the role of individual and contextual factors on premature ischemic heart disease mortality and to analyze how educational differentials in premature ischemic heart disease mortality changed during economic fluctuations in two provinces of Argentina from 1990 to 2018. To test the relationship between individual (age, sex, and educational level) and contextual (urbanization, poverty, and macroeconomic variations) factors, a multilevel Poisson model was estimated. When controlling for the level of poverty at the departmental level, we observed inequalities in premature ischemic heart disease mortality according to the educational level of individuals, affecting population of low educational level. Moreover, economic expansion was related to an increase in ischemic heart disease mortality, however, expansion years were not associated with increasing educational inequalities in ischemic heart disease mortality. At the departmental level, we found no contextual association beween area-related socioeconomic level and the risk of ischemic heart disease mortality. Despite the continuing decline in ischemic heart disease mortality in Argentina, this study highlighted that social inequalities in mortality risk increased over time. Therefore, prevention policies should be more focused on populations of lower socioeconomic status in Argentina.

Life and death during the Great Depression.

Recent events highlight the importance of examining the impact of economic downturns on population health. The Great Depression of the 1930s was the most important economic downturn in the U.S. in the twentieth century. We used historical life expectancy and mortality data to examine associations of economic growth with population health for the period 1920-1940. We conducted descriptive analyses of trends and examined associations between annual changes in health indicators and annual changes in economic activity using correlations and regression models. Population health did not decline and indeed generally improved during the 4 years of the Great Depression, 1930-1933, with mortality decreasing for almost all ages, and life expectancy increasing by several years in males, females, whites, and nonwhites. For most age groups, mortality tended to peak during years of strong economic expansion (such as 1923, 1926, 1929, and 1936-1937). In contrast, the recessions of 1921, 1930-1933, and 1938 coincided with declines in mortality and gains in life expectancy. The only exception was suicide mortality which increased during the Great Depression, but accounted for less than 2% of deaths. Correlation and regression analyses confirmed a significant negative effect of economic expansions on health gains. The evolution of population health during the years 1920-1940 confirms the counterintuitive hypothesis that, as in other historical periods and market economies, population health tends to evolve better during recessions than in expansions.

Are Wealthier Times Healthier in Cities? Economic Fluctuations and Mortality in Urban Areas of Latin America.

Objective: To analyze the relationship between economic conditions and mortality in cities of Latin America. Methods: We analyzed data from 340 urban areas in ten countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Guatemala, Mexico, Panama, Peru, and El Salvador. We used panel models adjusted for space-invariant and time-invariant factors to examine whether changes in area gross domestic product (GDP) per capita were associated with changes in mortality. Results: We find procyclical oscillations in mortality (i.e., higher mortality with higher GDP per capita) for total mortality, female population, populations of 0-9 and 45+ years, mortality due to cardiovascular diseases, malignant neoplasms, diabetes mellitus, respiratory infections and road traffic injuries. Homicides appear countercyclical, with higher levels at lower GDP per capita. Conclusions: Our results reveal large heterogeneity, but in our sample of cities, for specific population groups and causes of death, mortality oscillates procyclically, increasing when GDP per capita increases. In contrast we find few instances of countercyclical mortality.

Characterising variability and predictors of infant mortality in urban settings: findings from 286 Latin American cities.

BACKGROUND: Urbanisation in Latin America (LA) is heterogeneous and could have varying implications for infant mortality (IM). Identifying city factors related to IM can help design policies that promote infant health in cities. METHODS: We quantified variability in infant mortality rates (IMR) across cities and examined associations between urban characteristics and IMR in a cross-sectional design. We estimated IMR for the period 2014-2016 using vital registration for 286 cities above 100 000 people in eight countries. Using national censuses, we calculated population size, growth and three socioeconomic scores reflecting living conditions, service provision and population educational attainment. We included mass transit availability of bus rapid transit and subway. Using Poisson multilevel regression, we estimated the per cent difference in IMR for a one SD (1SD) difference in city-level predictors. RESULTS: Of the 286 cities, 130 had <250 000 inhabitants and 5 had >5 million. Overall IMR was 11.2 deaths/1000 live births. 57% of the total IMR variability across cities was within countries. Higher population growth, better living conditions, better service provision and mass transit availability were associated with 6.0% (95% CI -8.3 to 3.7%), 14.1% (95% CI -18.6 to -9.2), 11.4% (95% CI -16.1 to -6.4) and 6.6% (95% CI -9.2 to -3.9) lower IMR, respectively. Greater population size was associated with higher IMR. No association was observed for population-level educational attainment in the overall sample. CONCLUSION: Improving living conditions, service provision and public transportation in cities may have a positive impact on reducing IMR in LA cities.

Economic growth and mental health in 21st century China.

Though there are many inconsistencies in the literature, in market economies periods of economic growth, i.e., expansions, have been generally found associated with better mental health than economic contractions, i.e., recessions. This study investigates the association of economic conditions and mental health in China using three consecutive surveys of a cohort of over 17,000 adults aged 45 or older interviewed in 2011-12, 2013, and 2015 for the CHARLS study, totaling over 42,000 observations. Mental health was assessed by indicators of depression symptoms, cognition impairment, and life dissatisfaction. We found higher rates of GDP growth per capita associated with a deterioration of mental health, manifested by higher scores of depression symptoms, cognitive impairment, and life dissatisfaction. The effects were small in size, quite similar in men and women and were modified by level of income, with the population of lower income being the most harmed by economic growth.

The reversal of the relation between economic growth and health progress: Sweden in the 19th and 20th centuries.

Health progress, as measured by the decline in mortality rates and the increase in life expectancy, is usually conceived as related to economic growth, especially in the long run. In this investigation it is shown that economic growth is positively associated with health progress in Sweden throughout the 19th century. However, the relation becomes weaker as time passes and is completely reversed in the second half of the 20th century, when economic growth negatively affects health progress. The effect of the economy on health occurs mostly at lag 0 in the 19th century and is lagged up to 2 years in the 20th century. No evidence is found for economic effects on mortality at greater lags. These findings are shown to be robustly consistent across a variety of statistical procedures, including linear regression, spectral analysis, cross-correlation, and lag regression models. Models using inflation and unemployment as economic indicators reveal similar results. Evidence for reverse effects of health progress on economic growth is weak, and unobservable in the second half of the 20th century.

Economic fluctuations and educational inequalities in premature ischemic heart disease mortality in Argentina / Variaciones económicas y desigualdades educativas en la mortalidad prematura por enfermedad isquémica en Argentina / Flutuações econômicas e desigualdades educacionais na mortalidade prematura por doença isquêmica na Argentina

Abstract: Although mortality from ischemic heart disease has declined over the past decades in Argentina, ischemic heart disease remains one of the most frequent causes of death. This study aimed to describe the role of individual and contextual factors on premature ischemic heart disease mortality and to analyze how educational differentials in premature ischemic heart disease mortality changed during economic fluctuations in two provinces of Argentina from 1990 to 2018. To test the relationship between individual (age, sex, and educational level) and contextual (urbanization, poverty, and macroeconomic variations) factors, a multilevel Poisson model was estimated. When controlling for the level of poverty at the departmental level, we observed inequalities in premature ischemic heart disease mortality according to the educational level of individuals, affecting population of low educational level. Moreover, economic expansion was related to an increase in ischemic heart disease mortality, however, expansion years were not associated with increasing educational inequalities in ischemic heart disease mortality. At the departmental level, we found no contextual association beween area-related socioeconomic level and the risk of ischemic heart disease mortality. Despite the continuing decline in ischemic heart disease mortality in Argentina, this study highlighted that social inequalities in mortality risk increased over time. Therefore, prevention policies should be more focused on populations of lower socioeconomic status in Argentina.

Resumen: Si bien la mortalidad por cardiopatía isquémica ha disminuido en las últimas décadas en Argentina, la cardiopatía isquémica sigue siendo una de las causas más frecuentes de muerte. Los objetivos de este estudio fueron describir el papel de los factores individuales y contextuales en la mortalidad prematura por cardiopatía isquémica y analizar cómo estos cambiaron las diferencias educativas en la mortalidad prematura por cardiopatía isquémica durante las variaciones económicas en dos provincias de Argentina durante el periodo 1990-2018. Para probar la relación entre los factores individuales (edad, género y nivel de educación) y contextuales (urbanización, pobreza y variaciones macroeconómicas), se estimó un modelo de Poisson multinivel. Controlando el nivel de pobreza en el ámbito departamental, se observaron desigualdades en la mortalidad prematura por cardiopatía isquémica según el nivel de educación de los individuos, lo que afecta a la población con bajo nivel de educación; la expansión económica se relacionó con el aumento de la mortalidad por cardiopatía isquémica; sin embargo, el periodo de expansión no estuvo asociado a aumentos de las desigualdades educativas en la mortalidad por cardiopatía isquémica. En el ámbito departamental no se detectó asociación entre el nivel socioeconómico de la área y el riesgo de mortalidad por cardiopatía isquémica. A pesar de la disminución continua de la mortalidad por cardiopatía isquémica en Argentina, este estudio destaca que las desigualdades sociales con relación al riesgo de mortalidad tuvieron un aumento con el tiempo. Por lo tanto, las políticas de prevención deberán dirigirse más a las poblaciones de menor nivel socioeconómico en Argentina.

Resumo: Embora a mortalidade por doença isquêmica do coração tenha diminuído nas últimas décadas na Argentina, a doença isquêmica do coração continua sendo uma das causas mais frequentes de morte. Os objetivos deste estudo foram descrever o papel de fatores individuais e contextuais na mortalidade prematura por doença isquêmica do coração e analisar como as diferenças educacionais na mortalidade prematura por doença isquêmica do coração mudaram durante as flutuações econômicas em duas províncias da Argentina durante o período 1990-2018. Para testar a relação entre fatores individuais (idade, sexo e escolaridade) e contextuais (urbanização, pobreza e variações macroeconômicas), estimou-se um modelo de Poisson multinível. Controlando o nível de pobreza no nível departamental, observaram-se desigualdades na mortalidade prematura por doença isquêmica do coração de acordo com o nível educacional dos indivíduos, afetando a população de baixa escolaridade; a expansão econômica esteve relacionada ao aumento da mortalidade por doença isquêmica do coração; no entanto, os anos de expansão não foram associados a aumentos nas desigualdades educacionais na mortalidade por doença isquêmica do coração. No nível departamental, não foi detectada uma associação contextual entre nível socioeconômico da área e risco de mortalidade por doença isquêmica do coração. Apesar do contínuo declínio da mortalidade por doença isquêmica do coração na Argentina, este estudo destaca que as desigualdades sociais em relação ao risco de mortalidade aumentaram ao longo do tempo. Portanto, as políticas de prevenção devem ser mais focadas nas populações de menor nível socioeconômico na Argentina.

Impact of energy intake, physical activity, and population-wide weight loss on cardiovascular disease and diabetes mortality in Cuba, 1980-2005.

Cuba's economic crisis of 1989-2000 resulted in reduced energy intake, increased physical activity, and sustained population-wide weight loss. The authors evaluated the possible association of these factors with mortality trends. Data on per capita daily energy intake, physical activity, weight loss, and smoking were systematically retrieved from national and local surveys. National vital statistics from 1980-2005 were used to assess trends in mortality from diabetes, coronary heart disease, stroke, cancer, and all causes. The crisis reduced per capita daily energy intake from 2,899 calories to 1,863 calories. During the crisis period, the proportion of physically active adults increased from 30% to 67%, and a 1.5-unit shift in the body mass index distribution was observed, along with a change in the distribution of body mass index categories. The prevalence of obesity declined from 14% to 7%, the prevalence of overweight increased 1%, and the prevalence of normal weight increased 4%. During 1997-2002, there were declines in deaths attributed to diabetes (51%), coronary heart disease (35%), stroke (20%), and all causes (18%). An outbreak of neuropathy and a modest increase in the all-cause death rate among the elderly were also observed. These results suggest that population-wide measures designed to reduce energy stores, without affecting nutritional sufficiency, may lead to declines in diabetes and cardiovascular disease prevalence and mortality.

Increasing mortality during the expansions of the US economy, 1900-1996.

BACKGROUND: In Western countries mortality dropped throughout the 20th century, but over and above the long-term falling trend, the death rate has oscillated over time. It has been postulated that these short-term oscillations may be related to changes in the economy. METHODS: To ascertain if these short-term oscillations are related to fluctuations in the economy, age-adjusted total mortality and mortality for specific population groups, ages and causes of death were transformed into rate of change or percentage deviation from trend, and were correlated and regressed on indicators of the US economy during the 20th century, transformed in the same way. RESULTS: Statistically and demographically significant results show that the decline of total mortality and mortality for different groups, ages and causes accelerated during recessions and was reduced or even reversed during periods of economic expansion-with the exception of suicides which increase during recessions. In recent decades these effects are stronger for women and non-whites. CONCLUSIONS: Economic expansions are associated with increasing mortality. Suggested pathways to explain this deceleration or even reversal of the secular decline in mortality during economic expansions include both material and psychosocial effects of the economic upturns: expansion of traffic and industrial activity directly raising injury-related mortality, decreased immunity levels (owing to rising stress and reduction of sleep time, social interaction and social support), and increased consumption of tobacco, alcohol and saturated fats.

Health, economic crisis, and austerity: A comparison of Greece, Finland and Iceland.

Reports have attributed a public health tragedy in Greece to the Great Recession and the subsequent application of austerity programs. It is also claimed that the comparison of Greece with Iceland and Finland-where austerity policies were not applied-reveals the harmful effect of austerity on health and that by protecting spending in health and social budgets, governments can offset the harmful effects of economic crises on health. We use data on life expectancy, mortality rates, incidence of infectious diseases, rates of vaccination, self-reported health and other measures to examine the evolution of population health and health services performance in Greece, Finland and Iceland since 1990-2011 or 2012-the most recent years for which data are available. We find that in the three countries most indicators of population health continued improving after the Great Recession started. In terms of population health and performance of the health care system, in the period after 2007 for which data are available, Greece did as good as Iceland and Finland. The evidence does not support the claim that there is a health crisis in Greece. On the basis of the extant evidence, claims of a public health tragedy in Greece seem overly exaggerated.

[The economic crisis and health in Spain and Europe: is mortality increasing?]. / La crisis y la salud en España y en Europa: ¿Está aumentando la mortalidad?

In recent publications it has been suggested that the health of the European population is deteriorating as a consequence of the economic crisis. Such deterioration would be manifested by an increase in mortality, particularly in those countries applying austerity measures. It has also been suggested that as a consequence of these policies, suicides have skyrocketed and the situation could become a public health catastrophe of the kind that occurred in the 1990s in the countries formerly part of the USSR. These affirmations have no basis in the existing data. Statistics indicate that in European countries in general and especially in those most affected by the crisis, general mortality has decreased and the health of the population has improved in 2007-2010. Paradoxically, the crisis has had a beneficial effect on health in these countries. Such findings are in substantial agreement with previous studies that have shown throughout various periods within market economies that recessions are favorable to health while periods of economic expansion are harmful.

[Economic growth and health inequities]. / Crecimiento económico e inequidades en salud.

This essay reviews the relation between health inequities and economic growth. The general meaning of these and ancillary concepts (economic development, health inequalities) is briefly reviewed. Some studies illustrating different hypotheses on the long-run historical evolution of health inequalities are presented, and three case studies -the United States in 1920-1940 and in recent years, Finland during the expansion of the 1980s and the recession of the 1990s- are reviewed to demonstrate the evolution of health inequalities during the periods of expansion and recession in markets economies that conform to the so-called business cycle. Health inequities between ethnic groups and social classes are often found in modern societies, and some of these disparities seem to be widening. Periods of economic expansion do not seem favorable for the lessening of health inequalities. Contrarily, and counter-intuitively, evidence rather suggests that it is during periods of recession that gaps in health between privileged and disadvantaged groups tend to narrow.