Sanna Tiikkaja

Cancer risks in hairdressers: Assessment of carcinogenicity of hair dyes and gels

More than a decade ago, an increased risk for bladder cancer among male hairdressers was established. Frequent changes of hair dye formulations together with their widespread use call for safety guarantees. We carried out a follow‐up study of a cohort of 38,866 female and 6,824 male hairdressers from Sweden and analyzed all of their malignancies over a period of 39 years. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for 28 cancer sites were calculated using the economically active population as a reference. During the years 1960–1998 a total of 1,043 cancer cases were recorded in male hairdressers. Excess risks for cancers of the upper aerodigestive tract and lung and colorectal adenocarcinoma were observed. Additionally, male hairdressers working in 1960 had an increased risk for urinary bladder cancer, which was highest in the 1960s with an SIR of 2.56 (95% CI 1.36–4.39) and decreased with the follow‐up time. A total of 2,858 cancers were recorded in female hairdressers. An increased risk was observed for cancers of the pancreas, lung and cervix and in situ cancer of the skin. The increased risk for in situ skin cancer specifically affected the scalp and neck, sites of contact for hair dyes, with an SIR of 2.43 (95% CI 1.14–4.44). The increase in lung cancer, the only site for which cancer was increased in either sex, may depend on confounding from smoking. Bladder cancer was not increased among hairdressers in the recent decades and is therefore not likely to be associated with modern hair dyes.

Does intergenerational social mobility among men affect cardiovascular mortality? A population-based register study from Sweden

Background: Socioeconomic inequalities in cardiovascular mortality are well documented. The aim here is to examine the relation between childhood and adulthood class as well as the role of unique intergenerational social mobility trajectories in such mortality. Methods: Data were obtained from Swedish registries. Childhood and adulthood information were from the 1960 and 1990 censuses. Men born 1945—59 (809,199) were followed-up for four cardiovascular mortality outcomes 1990— 2002 (5533 deaths) by means of Cox regressions. Three different approaches were applied to study mobility between four main classes. Results: In mutually adjusted models, the effect of a manual adulthood class (compared with non-manuals) was clearly larger (hazard ratios (HR) were 1.56 for MI, 1.70 for stroke, 1.64 for other cardiovascular disease (CVD), 1.62 for all CVD) as for a manual childhood class (1.38, 1.17, 1.24 and 1.28, respectively). This also applied to unclassifiable, while there were few systematic findings for self-employed. When adjusting for education level, childhood class was still significant for MI, other and all CVD, but adulthood class was significant for all outcomes. Trajectory-specific analyses revealed that mobile men from non-manual to manual had significantly higher mortality than mobile from manual to non-manual and stable non-manuals, but not significantly lower than stable manuals. Conclusions: Cardiovascular mortality was clearly structured by adulthood class, but not as consistently structured by childhood class. The mediating role of education suggests that a major part of life-course disadvantages or advantages in relation to CVD was due to achieved education.

Intergenerational class mobility and cardiovascular mortality among Swedish women: A population-based register study☆

Class inequalities in cardiovascular disease (CVD) mortality are well documented, but the impact of intergenerational class mobility on CVD mortality among women has not been studied thoroughly. We examined whether womens mobility trajectories might contribute to CVD mortality beyond what could be expected from their childhood and adult social class position. The Swedish Work and Mortality Data Base provided childhood (1960) and adulthood (1990) social indicators. Women born 1945-59 (N=791 846) were followed up for CVD mortality 1990-2002 (2019 deaths) by means of logistic regression analysis. CVD mortality risks were estimated for 16 mobility trajectories. Gross and net impact of four childhood and four adult classes, based on occupation, were analysed for mortality in ischemic heart disease (IHD), stroke, other CVD, - and all CVD. Differences between the two most extreme trajectories were 10-fold, but the common trajectory of moving from manual to non-manual position was linked to only a slight excess mortality (OR=1.26) compared to the equally common trajectory of maintaining a stable non-manual position (reference category). Moving into adult manual class resulted in an elevated CVD mortality whatever the childhood position (ORs varied between 1.42 and 2.24). After adjustment for adult class, childhood class had some effect, in particular there was a low risk of coming from a self-employed childhood class on all outcomes (all ORs around=0.80). A womans own education had a stronger influence on the mortality estimates than did household income. Social mobility trajectories among Swedish women are linked to their CVD mortality risk. Educational achievement seems to be a key factor for intergenerational continuity and discontinuity in class-related risk of CVD mortality among Swedish women. However, on mutual adjustment, adult class was much more closely related to CVD mortality than was class in childhood.

Temporal Trends in Incidence of Myocardial Infarction and Ischemic Stroke by Socioeconomic Position in Sweden 1987–2010

Background We analyzed temporal trends in the incidence of myocardial infarction and ischemic stroke in Sweden by socioeconomic position and investigated whether social inequalities in incidence of these diseases changed over time. Materials and Methods We studied a cohort of almost three million Swedish residents born between 1932 and 1960 followed from 1987 until 2010. Incident cases of myocardial infarction and ischemic stroke were identified in the Swedish National Inpatient Register and Cause of Death Register. Socioeconomic position was retrieved from the Population and Housing Censuses. Incidence rates of myocardial infarction and ischemic stroke and incidence rate ratios comparing levels of socioeconomic position were estimated using flexible parametric survival models adjusted for calendar year, attained age, sex, and birth country. Results The overall incidences of myocardial infarction and ischemic stroke decreased over time among men, but were stable over time among women. With regard to ischemic stroke incidence, socioeconomic inequality increased over time in the age group 55 to 59: the incidence rate ratios for low manual compared to high non-manual increased from 1.3 (95% CI: 1.2–1.4) in 1997 to 1.5 (1.4–1.7) in 2010 among men, and from 1.4 (1.3–1.6) in 1997 to 2.1 (1.8–2.5) in 2010 among women. The socioeconomic inequality in incidence of myocardial infarction was stable over time for both men and women. Conclusion There was a decrease in myocardial infarction and ischemic stroke incidence over time among men but no significant change for women. Our study highlights existing, and in some cases increasing, social inequalities in the incidence of cardiovascular diseases.

Social Class, Social Mobility and Risk of Psychiatric Disorder - A Population-Based Longitudinal Study

Objectives This study explored how adult social class and social mobility between parental and own adult social class is related to psychiatric disorder. Material and Methods In this prospective cohort study, over 1 million employed Swedes born in 1949-1959 were included. Information on parental class (1960) and own mid-life social class (1980 and 1990) was retrieved from the censuses and categorised as High Non-manual, Low Non-manual, High Manual, Low Manual and Self-employed. After identifying adult class, individuals were followed for psychiatric disorder by first admission of schizophrenia, alcoholism and drug dependency, affective psychosis and neurosis or personality disorder (N=24 659) from the Swedish Patient Register. We used Poisson regression analysis to estimate first admission rates of psychiatric disorder per 100 000 person-years and relative risks (RR) by adult social class (treated as a time-varying covariate). The RRs of psychiatric disorder among the Non-manual and Manual classes were also estimated by magnitude of social mobility. Results The rate of psychiatric disorder was significantly higher among individuals belonging to the Low manual class as compared with the High Non-manual class. Compared to High Non-manual class, the risk for psychiatric disorder ranged from 2.07 (Low Manual class) to 1.38 (Low Non-manual class). Parental class had a minor impact on these estimates. Among the Non-manual and Manual classes, downward mobility was associated with increased risk and upward mobility with decreased risk of psychiatric disorder. In addition, downward mobility was inversely associated with the magnitude of social mobility, independent of parental class. Conclusions Independently of parental social class, the risk of psychiatric disorder increases with increased downward social mobility and decreases with increased upward mobility.

Maternal social characteristics and mortality from injuries among infants and toddlers in Estonia

Background: Injuries are a major cause of ill health among children, with a social gradient in child injuries documented in many countries. The effects of maternal sociodemographic characteristics on injury mortality in Estonian infants and toddlers were investigated. Methods: A population-based study using linkage of data from the Estonian Medical Birth Registry with Mortality Database. A total of 148 521 children born 1992–2002 were followed for injury mortality (ICD-9 E800-E999) from birth to third birthday. Associations of maternal age, education, marital status, nationality, place of residence and child’s birth order and multiplicity with risk of injury death were studied using logistic regression. Results: Maternal age (<20 years compared with ⩾30 years: OR 2.12; 95% CI 1.00 to 4.51), education (basic compared with secondary or higher: OR 3.22; 95% CI 2.12 to 4.87), marital status (single, divorced or widowed compared with married: OR 2.74; 95% CI 1.53 to 4.91), nationality (other compared with Estonian: OR 2.00; 95% CI 1.32 to 3.02), birth order (fourth or higher compared with first: OR 6.66; 95% CI 3.42 to 12.99), and multiple birth (twin or triplet compared with singleton: OR 3.12; 95% CI 1.44 to 6.73) affected the risk of injury death among infants (<1 year). Among toddlers (1–2 years), boys were at higher risk than girls (OR 1.75; 95% CI 1.15 to 2.66) and low mother’s education (basic compared with secondary or higher OR 2.08; 95% CI 1.28 to 3.37) and high birth order (fourth or higher compared with first: OR 7.88; 95% CI 3.90 to 15.90) increased the risk of injury death. Conclusions: Maternal sociodemographic characteristics are associated with injury mortality among infants and toddlers. Substantial variation in injury mortality rates within Estonia suggests potential for prevention.

Familial risk of premature cardiovascular mortality and the impact of intergenerational occupational class mobility

The negative impact of low social class on cardiovascular disease (CVD) and mortality has been consistently documented. However, less scientific consistency exists in terms of whether a unique health effect of social mobility from childhood to adulthood prevails. This study explored how childhood and adult social class and the transition between them (social mobility), are related to premature CVD mortality when familial aggregation of CVD among siblings is also considered. The study includes nearly 1.9 million Swedish residents born 1939-1959 distributed over 1,044,725 families, of whom 14,667 died prematurely from CVD in 1990-2003. Information on parental class (1960) and own mid-life occupational class (1990) was retrieved from the respective censuses. Odds ratios for premature CVD mortality according to trajectory-specific social mobility, along with pairwise mean odds ratios for sibling resemblance of premature CVD mortality, were calculated by means of alternating logistic regression. This model calculates the remaining dependency of CVD mortality within sibships after accounting for available risk factors (like parental and adult social class) in the population mean model. Results showed that premature CVD mortality was associated with both parental and own adult social class. A clear tendency for the downwardly mobile to have increased, and for the upwardly mobile to experience a decreased risk of premature CVD mortality was found, as well as a corresponding unique effect of social mobility per se among the manual and non-manual classes. This effect was verified for men, but not for women, when they were analysed separately. The pairwise mean odds ratios for premature CVD mortality among full siblings were 1.78 (95% CI: 1.52-2.08), and were independent of parental CVD mortality and parental or adult occupational class.

Psychiatric disorder and work life: A longitudinal study of intra-generational social mobility.

Background: Intra-generational social mobility, which describes the mobility within an individual’s own working life, is seldom studied among employees with psychiatric disorders (EPD). There is need of knowledge of the intra-generational mobility patterns, in a broader perspective, among EPD. Aims: To investigate intra-generational social mobility in employed individuals diagnosed with affective disorder, personality disorder, schizophrenia and drug dependence in a national Swedish cohort. Method: We identified a national sample of employed Swedish adults born in 1939–1949 (N = 876, 738), and among them individuals with a first-time hospital admission for affective psychosis, neurosis and personality disorder, alcoholism, drug dependence or schizophrenia in 1964–1980 (N = 18, 998). Employed individuals without hospital admission for such diagnoses were utilised as a comparison group (N = 866, 442). Intra-individual social class changes between 1980 and 1990 among EPD and the comparison group were described through summary statistics and graphs. Results: EPD more often held Low manual occupations at baseline in 1980 than the comparison group (44% vs. 28%), although parental social class was similar. In 1990, 19% of EPD and 4% of the comparison group had lost contact with the labour market. Social stability was less common among EPD (49 %) than in the comparison group (67%). Mobility out of the labour force increased and social stability decreased by number of inpatient admissions. Employees diagnosed with affective psychosis or neurosis and personality disorder fared better in the labour market than employees with schizophrenia. Conclusion: Employees suffering from psychiatric disorder do not maintain their social class or remain in the labour force to the same extent as individuals without those problems, irrespective of their parental class. Our results support the social drift hypothesis that individuals with poor psychiatric health move downward in the social hierarchy.

Trends in incidence of cardiovascular diseases by social class in Sweden 1987–2010

The IEA-EEF European Congress of Epidemiology 2012: Epidemiology for a Fair and Healthy Society ! Springer Science+Business Media B.V. 2012 Epidemiology for a fair and healthy society: Euroepi 2012