Diminishing educational differences in breast cancer mortality among Finnish women: a register-based 25-year follow-up

Changing patterns of breast cancer incidence and mortality by education level over four decades in Norway, 1971-2009

Background

In the last century, breast cancer incidence and mortality was higher among higher versus lower educated women in developed countries. Post-millennium, incidence rates have flattened off and mortality declined. We examined breast cancer trends by education level, to see whether recent improvements in incidence and mortality rates have occurred in all education groups.

Methods

We linked individual registry data on female Norwegian inhabitants aged 35 years and over during 1971–2009. Using Poisson models, we calculated absolute and relative educational differences in age-standardised breast cancer incidence and mortality over four decades. We estimated educational differences by Slope and Relative Index of Inequality, which correspond to rate difference and rate ratio, comparing the highest to lowest educated women.

Results

Pre-millennium, incidence and mortality of breast cancer were significantly higher in higher versus lower educated women. Post-millennium, educational differences in breast cancer incidence and mortality attenuated. During 2000–2009, breast cancer incidence was still 38% higher for higher versus lower educated women (Relative Index of Inequality: 1.38, 95% confidence interval: 1.31–1.44), but mortality no longer varied significantly by education level (Relative Index of Inequality: 1.09, 95% confidence interval: 0.99–1.19). Among women below 50 years, however, the education gradient for mortality reversed, and mortality was 28% lower for the highest versus lowest educated women during 2000–2009 (Relative Index of Inequality: 0.72, 95% confidence interval: 0.51–0.93).

Results

Post-millennium improvements in breast cancer incidence and mortality have primarily benefited higher educated women. Breast cancer mortality is now highest among the lowest educated women below 50 years.

Increased breast cancer mortality only in the lower education group: age-period-cohort effect in breast cancer mortality by educational level in South Korea, 1983-2012

BACKGROUND

A steadily increasing pattern of breast cancer mortality has been reported in South Korea since the late 1980s. This paper explored the trends of educational inequalities of female breast cancer mortality between 1983 and 2012 in Korea, and conducted age-period-cohort (APC) analysis by educational level.

METHODS

Age-standardized mortality rates of breast cancer per 100,000 person-years were calculated. Relative index of inequality (RII) for breast cancer mortality was used as an inequality measure. APC analyses were conducted using the Web tool for APC analysis provided by the Division of Cancer Epidemiology and Genetics at the U.S. National Cancer Institute.

RESULTS

An increasing trend in breast cancer mortality among Korean women between 1983 and 2012 was due to the increased mortality of the lower education groups (i.e., no formal education or primary education and secondary education groups), not the highest education group. The breast cancer mortality was higher in women with a tertiary education than in women with no education or a primary education during 1983-1992, and the reverse was true in 1993-2012. Consequently, RII was changed from positive to negative associations in the early 2000s. The lower education groups had the increased breast cancer mortality and significant cohort and period effects between 1983 and 2012, whereas the highest group did not.

CONCLUSIONS

APC analysis by socioeconomic position used in this study could provide an important clue for the causes on breast cancer mortality. The long-term monitoring of socioeconomic patterning in breast cancer risk factors is urgently needed.

Trends in educational inequalities in premature mortality in Belgium between the 1990s and the 2000s: the contribution of specific causes of deaths

BACKGROUND

Reducing socioeconomic inequalities in mortality, a key public health objective may be supported by a careful monitoring and assessment of the contributions of specific causes of death to the global inequality.

METHODS

The 1991 and 2001 Belgian censuses were linked with cause-of-death data, each yielding a study population of over 5 million individuals aged 25-64, followed up for 5 years. Age-standardised mortality rates (ASMR) were computed by educational level (EL) and cause. Inequalities were measured through rate differences (RDs), rate ratios (RRs) and population attributable fractions (PAFs). We analysed changes in educational inequalities between the 1990s and the 2000s, and decomposed the PAF into the main causes of death.

RESULTS

All-cause and avoidable ASMR decreased in all ELs and both sexes. Lung cancer, ischaemic heart disease (IHD), chronic obstructive pulmonary disease (COPD) and suicide in men, and IHD, stroke, lung cancer and COPD in women had the highest impact on population mortality. RDs decreased in men but increased in women. RRs and PAFs increased in both sexes, albeit more in women. In men, the impact of lung cancer and COPD inequalities on population mortality decreased while that of suicide and IHD increased. In women, the impact of all causes except IHD increased.

CONCLUSION

Absolute inequalities decreased in men while increasing in women; relative inequalities increased in both sexes. The PAFs decomposition revealed that targeting mortality inequalities from lung cancer, IHD, COPD in both sexes, suicide in men and stroke in women would have the largest impact at population level.

Differences in mortality among women with breast cancer by income – a register-based study in Finland

Aims: The aim was to assess all-cause and breast cancer mortality by income among women with incident breast cancer and the effect of cancer stage at diagnosis and comorbidity on the differences. Methods: The 43,439 women (age ⩾30) diagnosed with breast cancer in 1998–2008 in Finland were monitored using individual-level Cancer Registry data supplemented with data from Finnish health care registers and sociodemographic data. Results: Overall mortality was greater among breast cancer patients of the lowest income group than in the highest one; the hazard ratio (HR) for age and incidence year adjusted all-cause mortality was 1.9 (95% CI 1.8–2.1) and for breast cancer mortality 2.0 (95% CI 1.8–2.2). The women from the lowest income group were over-represented in the breast cancer stage ‘distant’ (10.1% vs. 3.5% among the highest income group). The presence of comorbidities was more common in patients with the lowest income (at least one comorbidity in 54%) than in the highest (24%). The HR adjusted with stage at presentation and comorbidities was 1.6 (95% CI 1.4–1.7) for all-cause mortality and 1.6 (95% CI 1.4–1.7) for breast cancer mortality. Conclusions: Tumour stage at diagnosis was more severe among lower income groups, and the presence of comorbidities was more common, although this only accounted for a part of the higher breast cancer mortality in these groups. More information is needed about recognition, diagnosis and treatment of breast cancer to examine whether the socioeconomic differences of breast cancer mortality are related to care.

Diverging trends in educational inequalities in cancer mortality between men and women in the 2000s in France

BACKGROUND

Socioeconomic inequalities in cancer mortality have been observed in different European countries and the US until the end of the 1990s, with changes over time in the magnitude of these inequalities and contrasted situations between countries. The aim of this study is to estimate relative and absolute educational differences in cancer mortality in France between 1999 and 2007, and to compare these inequalities with those reported during the 1990s.

METHODS

Data from a representative sample including 1% of the French population were analysed. Educational differences among people aged 30-74 were quantified with hazard ratios and relative indices of inequality (RII) computed using Cox regression models as well as mortality rate difference and population attributable fraction.

RESULTS

In the period 1999-2007, large relative inequalities were found among men for total cancer and smoking and/or alcohol related cancers mortality (lung, head and neck, oesophagus). Among women, educational differences were reported for total cancer, head and neck and uterus cancer mortality. No association was found between education and breast cancer mortality. Slight educational differences in colorectal cancer mortality were observed in men and women. For most frequent cancers, no change was observed in the magnitude of relative inequalities in mortality between the 1990s and the 2000s, although the RII for lung cancer increased both in men and women. Among women, a large increase in absolute inequalities in mortality was observed for all cancers combined, lung, head and neck and colorectal cancer. In contrast, among men, absolute inequalities in mortality decreased for all smoking and/or alcohol related cancers.

CONCLUSION

Although social inequalities in cancer mortality are still high among men, an encouraging trend is observed. Among women though, the situation regarding social inequalities is less favourable, mainly due to a health improvement limited to higher educated women. These inequalities may be expected to further increase in future years.

The enduring and evolving relationship between social class and breast cancer burden: a review of the literature

INTRODUCTION

Breast cancer in women has historically been seen as a "cancer of affluence" and there is a well-documented higher incidence among women of higher social class, as well as in societies with higher resources. However, the relationship between social class and breast cancer disease characteristics, especially those associated with poorer prognosis, is less well documented, and the overall relationship between breast cancer mortality and social class has been shown to vary. Furthermore, rapid changes in women's health and health-related behaviors in societies around the world may have an impact on both incidence and mortality patterns for breast cancer in the future.

METHODS

A PUBMED search on breast cancer and social class (incorporating the MeSH-nested concept of SES) yielded 403 possible studies published between 1978 and 2009, of which 90 met criteria for review. Our review discusses conceptualization and measurement of women's social class in each study, as well as findings related to breast cancer incidence, tumor biology or mortality, associated with social class.

FINDINGS

We found mostly consistent evidence that breast cancer incidence continues to be higher in higher social class groups, with some modification of risk with adjustment for known risk factors, including physical activity and reproductive history. However, biologic characteristics associated with poorer prognosis were negatively associated with social class (i.e., greater occurrence among disadvantaged women), and mortality from breast cancer showed inconsistent relationship to social class.

CONCLUSIONS

We discuss these studies in relation to the growing burden of breast cancer among low resource groups and countries, and the need for cancer control strategies reflecting the emerging demographics of breast cancer risk.

A prospective study of educational background and breast cancer among Japanese women

OBJECTIVE

This prospective cohort study examined the association between educational level and breast cancer incidence in Japan.

METHOD

A baseline survey was conducted between 1988 and 1990 among 110,792 residents of 45 areas, aged 40-79 years. Data were restricted to 24 areas where incidence registry data were available, and to subjects which provided information on educational level (32,646). The subjects were assigned to three groups according to their level of education (<16, 16-18, 18<). During 13 years of follow-up (328,931 person-year), 169 cases of breast cancer were newly diagnosed.

RESULTS

Women with a high level of education had an increased risk of breast cancer (HR = 1.93, 95 percent confidence interval (95% CI): 1.18, 3.16, in women with the highest educational level) compared with women with the lowest educational level. Adjustment for lifestyle and reproductive factors did not substantially change the results. In addition, when analyses were stratified by age subgroups, the educational difference in breast cancer incidence was more evident among the younger than the elder subgroup.

CONCLUSION

The present results suggested that cancer prevention strategies should recognize women with a higher educational level as a high risk group for breast cancer.

Educational differences in cancer mortality among women and men: a gender pattern that differs across Europe

We used longitudinal mortality data sets for the 1990s to compare socioeconomic inequalities in total cancer mortality between women and men aged 30–74 in 12 different European populations (Madrid, Basque region, Barcelona, Slovenia, Turin, Switzerland, France, Belgium, Denmark, Norway, Sweden, Finland) and to investigate which cancer sites explain the differences found. We measured socioeconomic status using educational level and computed relative indices of inequality (RII). We observed large variations within Europe for educational differences in total cancer mortality among men and women. Three patterns were observed: Denmark, Norway and Sweden (significant RII around 1.3–1.4 among both men and women); France, Switzerland, Belgium and Finland (significant RII around 1.7–1.8 among men and around 1.2 among women); Spanish populations, Slovenia and Turin (significant RII from 1.29 to 1.88 among men; no differences among women except in the Basque region, where RII is significantly lower than 1). Lung, upper aerodigestive tract and breast cancers explained most of the variations between gender and populations in the magnitude of inequalities in total cancer mortality. Given time trends in cancer mortality, the gap in the magnitude of socioeconomic inequalities in cancer mortality between gender and between European populations will probably decrease in the future.

Educational differences in all-cause mortality by marital status - Evidence from Bulgaria, Finland and the United States

Using life table measures, we compare educational differentials in all-cause mortality at ages 40 to 70 in Bulgaria to those in Finland and the United States. Specifically, we assess whether the relationship between education and mortality is modified by marital status. Although high education and being married are associated with lower mortality in all three countries, absolute educational differences tend to be smaller among married than unmarried individuals. Absolute differentials by education are largest for Bulgarian men, but in relative terms educational differences are smaller among Bulgarian men than in Finland and the U.S. Among women, Americans experience the largest education-mortality gradients in both relative and absolute terms. Our results indicate a particular need to tackle health hazards among poorly educated men in countries in transition.

Cancer mortality in the United States by education level and race

BACKGROUND

Although both race and socioeconomic status are well known to influence mortality patterns in the United States, few studies have examined the simultaneous influence of these factors on cancer incidence and mortality. We examined relationships among race, education level, and mortality from cancers of the lung, breast, prostate, colon and rectum, and all sites combined in contemporary US vital statistics.

METHODS

Age-adjusted cancer death rates (with 95% confidence intervals [CIs]) were calculated for 137,708 deaths among 119,376,196 individuals aged 25-64 years, using race and education information from death certificates and population denominator data from the US Bureau of the Census, for 47 states and Washington, DC, in 2001. Relative risk (RR) estimates were used to compare cancer death rates in persons with 12 or fewer years of education with those in persons with more than 12 years of education.

RESULTS

Educational attainment was strongly and inversely associated with mortality from all cancers combined in black and white men and in white women. The all-cancer death rates were nearly identical for black men and white men with 0-8 years of education (224.2 and 223.6 per 100,000, respectively). The estimated relative risk for all-cancer mortality comparing the three lowest (< or = 12 years) with the three highest (> 12 years) education categories was 2.38 (95% CI = 2.33 to 2.43) for black men, 2.24 (95% CI = 2.23 to 2.26) for white men, 1.43 (95% CI = 1.41 to 1.46) for black women, and 1.76 (95% CI = 1.75 to 1.78) for white women. For both men and women, the magnitude of the relative risks comparing the three lowest educational levels with the three highest within each race for all cancers combined and for lung and colorectal cancers was higher than the magnitude of the relative risks associated with race within each level of education, whereas for breast and prostate cancer the magnitude of the relative risks associated with race was higher than the magnitude of the relative risks associated with level of education within each racial group. Among the most important and novel findings were that black men who completed 12 or fewer years of education had a prostate cancer death rate that was more than double that of black men with more schooling (10.5 versus 4.8 per 100,000 men; RR = 2.17, 95% CI = 1.82 to 2.58) and that, in contrast with studies of mortality rates in earlier time periods, breast cancer mortality rates were higher among women with less education than among women with more education (37.0 and 31.1 per 100,000, respectively, for black women and 25.2 versus 18.6 per 100,000, respectively, for white women).

CONCLUSION

Cancer death rates vary considerably by level of education. Identifying groups at high risk of death from cancer by level of education as well as by race may be useful in targeting interventions and tracking cancer disparities.

Health behaviours as explanations for educational level differences in cardiovascular and all-cause mortality: a follow-up of 60 000 men and women over 23 years

BACKGROUND

Health behaviours are potential explanatory factors for socioeconomic differences in mortality. We examined the extent to which seven health behaviours covering dietary habits, smoking and physical activity, can account for relative differences in cardiovascular and all-cause mortality by educational level.

METHODS

Health behaviour data derived from nationwide Finnish health behaviour surveys from the years 1979 to 2001. These annually repeated cross-sectional surveys were linked to register-based information on educational level and subsequent mortality from the year of the survey until the end of 2001 (average follow-up time 11.9 years). The analyses included 29 065 men and 31 543 women of whom 4263 died. Cardiovascular disease (CVD), coronary heart disease (CHD), stroke and all-cause mortality was studied.

RESULTS

Educational level showed a graded association with all mortality outcomes. Health behaviours explained 54% of the relative difference between primary and higher educational level in CVD mortality among in men and 22% among in women. For all-cause mortality the corresponding figures were 45 and 38%. Smoking, vegetable use and physical activity were the most important health behaviours explaining educational level differences in all mortality outcomes, while the effects of type of fat used on bread, coffee drinking, relative weight and alcohol use were small.

CONCLUSIONS

Smoking, low vegetable use and physical inactivity explained a substantial part of educational level differences in cardiovascular and all-cause mortality among men and women. Socioeconomic trends in these behaviours are of crucial importance in determining whether socioeconomic mortality differences will widen or narrow in the future.

Municipal distribution of breast cancer mortality among women in Spain

Background

Spain has one of the lowest rates of breast cancer in Europe, though estimated incidence has risen substantially in recent decades. Some years ago, the Spanish Cancer Mortality Atlas showed Spain as having a heterogeneous distribution of breast cancer mortality at a provincial level. This paper describes the municipal distribution of breast cancer mortality in Spain and its relationship with socio-economic indicators.

Methods

Breast cancer mortality was modelled using the Besag-York-Molliè autoregressive spatial model, including socio-economic level, rurality and percentage of population over 64 years of age as surrogates of reproductive and lifestyle risk factors. Municipal relative risks (RRs) were independently estimated for women aged under 50 years and for those aged 50 years and over. Maps were plotted depicting smoothed RR estimates and the distribution of the posterior probability of RR>1.

Results

In women aged 50 years and over, mortality increased with socio-economic level, and was lower in rural areas and municipalities with higher proportion of old persons. Among women aged under 50 years, rurality was the only statistically significant explanatory variable.

For women older than 49 years, the highest relative risks were mainly registered for municipalities located in the Canary Islands, Balearic Islands, the Mediterranean coast of Catalonia and Valencia, plus others around the Ebro River. In premenopausal women, the pattern was similar but tended to be more homogeneous. In mainland Spain, a group of municipalities with high RRs were located in Andalusia, near the left bank of the Guadalquivir River.

Conclusion

As previously observed in other contexts, mortality rates are positively related with socio-economic status and negatively associated with rurality and the presence of a higher proportion of people over age 64 years. Taken together, these variables represent the influence of lifestyle factors which have determined the increase in breast cancer frequency over recent decades. The results for the younger group of women suggest an attenuation of the socio-economic gradient in breast cancer mortality in Spain. The geographical variation essentially suggests the influence of other environmental variables, yet the descriptive nature of this study does not allow for the main determinants to be established.

The reversed social gradient: higher breast cancer mortality in the higher educated compared to lower educated. A comparison of 11 European populations during the 1990s

Higher socioeconomic position has been reported to be associated with increased risk of breast cancer mortality. Our aim was to see if this is consistently observed within 11 European populations in the 1990s. Longitudinal data on breast cancer mortality by educational level and marital status were obtained for Finland, Norway, Denmark, England and Wales, Belgium, France, Switzerland, Austria, Turin, Barcelona and Madrid. The relationship between breast cancer mortality and education was summarised by means of the relative index of inequality. A positive association was found in all populations, except for Finland, France and Barcelona. Overall, women with a higher educational level had approximately 15% greater risk of dying from breast cancer than those with lower education. This was observed both among never- and ever-married women. The greater risk of breast cancer mortality among women with a higher level of education was a persistent and generalised phenomenon in Europe in the 1990s.

Cancer is overtaking cardiovascular disease as the main driver of socioeconomic inequalities in mortality: New Zealand (1981-99)

BACKGROUND

Relative socioeconomic disparities in cardiovascular mortality have increased in New Zealand, as in many Western countries in Northern Europe, the US and Australia during the late 20th century. However, substantial declines in cardiovascular mortality mean that its absolute contribution to overall mortality has decreased.

RESEARCH QUESTIONS

How did the absolute contribution of major causes of death to socioeconomic inequalities in New Zealand change during the 1980s and 90s?

METHODS

Linked census-mortality cohorts were used to calculate the contribution of different causes of death to inequalities in mortality, measured with the slope index of inequality, by household income.

RESULTS

Between 1981-4 and 1996-9, the contribution of cardiovascular disease (CVD) to total inequality declined from 55% to 28% among women, whereas at the same time the contribution of cancers increased from 14% to 37%. Among men, the contribution of CVD to total inequality peaked at 47% in 1986-9, then declined to 38% in 1996-9. The contribution of cancer increased from 19% to 26% in men.

CONCLUSION

CVD mortality has declined at all income levels and so too has the contribution of CVD to mortality inequalities. Concurrently, the contribution of cancer to inequalities in mortality by income has increased and, in women at least, is now greater than the contribution of CVD. It is hypothesised that a similar crossover is occurring in other populations where CVD mortality has declined, although socioeconomic differences in the distribution and effect of the obesity epidemic for CVD may ensure its continuing importance. Prevention efforts aimed at reducing socioeconomic inequalities in mortality will need to increasingly focus on socioeconomic inequalities in cancer mortality.

Lifelong socioeconomic trajectory and premature mortality (35-65 years) in France: findings from the GAZEL Cohort Study

BACKGROUND

Studies conducted in the UK and Scandinavia show an inverse association between lifetime socioeconomic position and adult mortality. However, there are virtually no data from other countries and few investigations have examined non-cardiovascular mortality in men and women.

METHODS

Lifelong socioeconomic trajectories (father's occupation, own occupation in young adulthood and in mid-life) and premature (< or = 65 years) mortality (all-cause, smoking-related cancer, diseases of the circulatory system and external causes) in the French GAZEL Cohort Study (14,972 men and 5,598 women, followed up between 1990 and 2004) were studied. Hazard ratios (HRs) were estimated using Cox's regression models adjusted for age, marital status, tobacco smoking, alcohol consumption, body mass index, and fruit and vegetable consumption.

RESULTS

Men and women who experienced lifelong disadvantage or downward intergenerational mobility were at high risk of dying prematurely compared with those with a favourable trajectory (age-adjusted HRs for all-cause mortality: cumulative disadvantage: HR 1.61, 95% confidence interval (CI) 1.26 to 2.06 in men and HR 1.95, 95% CI 1.10 to 3.47 in women; downward mobility: HR 1.87, 95% CI 1.35 to 2.58 in men and HR 2.05, 95% CI 1.12 to 3.75 in women). Associations were strongest for mortality due to chronic diseases (smoking-related cancers and diseases of the circulatory system). These associations were partly explained by marital status, body mass index, alcohol consumption, cigarette smoking, and fruit and vegetable consumption.

CONCLUSIONS

In France, where the leading cause of premature death is cancer, lifelong socioeconomic position is associated with the risk of dying before the age of 65 years. Adult factors seem more relevant than childhood socioeconomic circumstances.

Patterns of disparity: ethnic and socio-economic trends in breast cancer mortality in New Zealand

OBJECTIVE

To test whether trends in breast cancer mortality varied by ethnicity and socio-economic position during the 1980s and '90s in New Zealand.

METHODS

Four cohorts of the entire New Zealand population for 1981-84; 86-89; 91-94 and 96-99 allowed direct determination of socio-economic trends in breast cancer mortality. For ethnicity, unlinked routine census and mortality data were used with adjustment factors for undercounting of Māori and Pacific deaths.

RESULTS

Māori and non-Māori non-Pacific mortality rates changed little until mid-1990s with Māori experiencing 25% higher mortality. In 1996-99, Māori rates increased notably to become 68% higher than non-Māori non-Pacific (SRR 1.68; 95% CI: 1.49-1.90). Pacific women experienced an approximate three-fold increase in breast cancer mortality over time. There appeared to be reducing mortality among higher income and education groups but trends within socio-economic groups were not statistically significant. Nevertheless, by 1996-99, there was a significant 22% excess mortality (SRR 1.22; 95% CI: 1.01-1.49) for low compared with high-income groups.

CONCLUSIONS

Widening ethnic, and probably, socio-economic disparities in breast cancer mortality are likely due to both underlying incidence and differential survival trends. Disparities are likely to increase once the full differential mortality benefits of screening impact on the population.

Social inequalities in breast cancer mortality among French women: disappearing educational disparities from 1968 to 1996

We investigated the time trends in social inequalities in breast cancer mortality with an analysis by age at death and birth cohort using a representative 1% sample of the French population and four subcohorts (1968–1974, 1975–1981, 1982–1988 and 1990–1996). Causes of death were obtained by direct linkage with the French national death registry. Education was measured at the beginning of each period, and educational disparities in breast cancer mortality were studied among women aged 35–74 at the beginning of each period. In the 1970s, higher breast cancer mortality was found among higher educated women. This positive association progressively weakened and no association remained in the 1990s although it disappeared earlier among younger women. In an analysis by birth cohort, the same pattern was found among women born before 1925, whereas no association between education and mortality was observed among women born after 1925. Educational disparities in breast cancer mortality are currently changing and the previously observed positive gradient has disappeared. An important question is whether these relations are indirect, and due to changes in the prevalence of risk factors associated with education, but which we could not study.

Occupational class, occupational mobility and cancer incidence among middle-aged men and women: a prospective study of the French GAZEL cohort*

OBJECTIVE

To examine the association between occupational class, occupational mobility and cancer incidence in the 1990s.

METHODS

Prospective study of 14,853 men and 5493 women employed by a large French company. Incident cases (any cancer, smoking and alcohol-related, breast) were ascertained through a validated company-based cancer registry (1990-2002). Hazard ratios (HRs) by occupational class and by career-long occupational mobility were calculated adjusting for age, marital status, tobacco and alcohol consumption, weight, diet, asbestos exposure, family history of cancer, and reproductive history.

RESULTS

359 male cancers (107 smoking and alcohol-related) and 208 female cases (120 breast cancers) were observed. Male clerks and manual workers were at high risk, particularly of smoking and alcohol-related cancers (compared to managers, age-adjusted HRs: 2.95 95% CI 1.37-6.38 and 2.18 95% CI 1.15-4.11). Adjusting for specific health behaviors and other cancer risk factors reduced this gradient (fully-adjusted HRs respectively 1.95 95% CI 0.89-4.27 and 1.54 95% CI 0.80-2.97). The risk was also associated with occupational mobility. We found no association between women's occupational class and cancer.

CONCLUSION

The incidence of smoking and alcohol-related cancers among French men shows a strong socioeconomic gradient. Policies addressing these social disparities are needed.

Does stage at diagnosis influence the observed relationship between socioeconomic status and breast cancer incidence, case-fatality, and mortality?

Historically, lower socioeconomic status (SES) has been reported to be associated with decreased breast cancer incidence and mortality and increased case-fatality, although recent trends in breast cancer screening and treatment may alter these relationships. This study assessed the associations between SES and breast cancer incidence, case-fatality, and mortality by stage of disease at diagnosis using recent data in the United States. Breast cancer incidence and survival data from the Surveillance, Epidemiology, and End Results (SEER) tumor registry for black and white women aged 55 and above were linked to county level SES and population data based on place of residence. Poisson regression was used to calculate age-adjusted relative rates associated with SES levels and breast cancer incidence, case-fatality, and mortality. As SES decreased, localized breast cancer incidence rates decreased, while incidence rates of distant disease increased. Five-year localized and regional breast cancer case-fatality rates increased as SES decreased. Localized breast cancer mortality rates decreased as SES declined, whereas regional breast cancer mortality rates tended to increase. These results confirm some previously reported findings and suggest that associations between lower SES and lower localized breast cancer mortality rates are influenced mainly by underlying associations between SES and localized breast cancer incidence, whereas regional breast cancer mortality rates appear to reflect the underlying association between SES and regional case-fatality rates.

Widening socioeconomic inequalities in mortality in six Western European countries

OBJECTIVES

During the past decades a widening of the relative gap in death rates between upper and lower socioeconomic groups has been reported for several European countries. Although differential mortality decline for cardiovascular diseases has been suggested as an important contributory factor, it is not known what its quantitative contribution was, and to what extent other causes of death have contributed to the widening gap in total mortality.

METHODS

We collected data on mortality by educational level and occupational class among men and women from national longitudinal studies in Finland, Sweden, Norway, Denmark, England/Wales, and Italy (Turin), and analysed age-standardized death rates in two recent time periods (1981-1985 and 1991-1995), both total mortality and by cause of death. For simplicity, we report on inequalities in mortality between two broad socioeconomic groups (high and low educational level, non-manual and manual occupations).

RESULTS

Relative inequalities in total mortality have increased in all six countries, but absolute differences in total mortality were fairly stable, with the exception of Finland where an increase occurred. In most countries, mortality from cardiovascular diseases declined proportionally faster in the upper socioeconomic groups. The exception is Italy (Turin) where the reverse occurred. In all countries with the exception of Italy (Turin), changes in cardiovascular disease mortality contributed about half of the widening relative gap for total mortality. Other causes also made important contributions to the widening gap in total mortality. For these causes, widening inequalities were sometimes due to increasing mortality rates in the lower socioeconomic groups. We found rising rates of mortality from lung cancer, breast cancer, respiratory disease, gastrointestinal disease, and injuries among men and/or women in lower socioeconomic groups in several countries.

CONCLUSIONS

Reducing socioeconomic inequalities in mortality in Western Europe critically depends upon speeding up mortality declines from cardiovascular diseases in lower socioeconomic groups, and countering mortality increases from several other causes of death in lower socioeconomic groups.

Socioeconomic status and breast cancer in Denmark

BACKGROUND

Breast cancer is the most frequent cancer in women and the incidence has increased over time. Our objectives were to study: (1) the socioeconomic differences in breast cancer incidence and mortality in Denmark, (2) how different socioeconomic groups have contributed to the increasing incidence, (3) whether the diverging trend between breast cancer incidence and mortality reflects different socioeconomic distributions of breast cancer cases and breast cancer deaths, and (4) to compare measures of socioeconomic status based on own and spouses' occupation, respectively. We addressed these questions by studying the socioeconomic distribution of breast cancer incidence and breast cancer mortality in Danish women during the last 25 years.

METHODS

In all 1 402 225 women in Denmark were individually followed up for death, emigration, and incident breast cancer in 1970-1995. Of the 1 402 225 women included in the study, 730 549 were economically active in 1970, and 480 379 women were both married and economically active. Socioeconomic status was assessed based on the occupation in 1970.

RESULTS

For all women classified by their own socioeconomic group, the standardized incidence (SIR) and the standardized mortality ratios (SMR) were highest in academics (SIR = 1.39, SMR = 1.29), and lowest in women in agriculture (SIR = 0.77, SMR = 0.75). For married, economically active women classified by their own socioeconomic group the SIR and SMR were highest in academics (SIR = 1.40, SMR = 1.44) and lowest in women in agriculture (SIR = 0.76, SMR = 0.76). Classified by their husbands' socioeconomic group, the SIR and SMR were highest in women married to academics (SIR = 1.21, SMR = 1.16) and lowest in women married to men in agriculture (SIR = 0.79, SMR = 0.79). From 1970 to 1995, the risk of developing breast cancer increased by 38% in women aged 50-64. All social groups contributed to this increase, the increase being 45% in unskilled workers, and 26% in academics.

CONCLUSION

During the last quarter of the 20th century academics had the highest risk of breast cancer in Denmark. The size of the social gradient in breast cancer occurrence depended on the measure used. The time trends in social distribution will result in breast cancer becoming more frequent.