Social gradients in ADHD by household income and maternal education exposure during early childhood : findings from birth cohort studies across six countries

Objective: This study aimed to examine social gradients in ADHD during late childhood (age 9–11 years) using absolute and relative relationships with socioeconomic status exposure (household income, maternal education) during early childhood (<5 years) in seven cohorts from six industrialised countries (UK, Australia, Canada, The Netherlands, USA, Sweden). Methods: Secondary analyses were conducted for each birth cohort. Risk ratios, pooled risk estimates, and absolute inequality, measured by the Slope Index of Inequality (SII), were estimated to quantify social gradients in ADHD during late childhood by household income and maternal education measured during early childhood. Estimates were adjusted for child sex, mother age at birth, mother ethnicity, and multiple births. Findings: All cohorts demonstrated social gradients by household income and maternal education in early childhood, except for maternal education in Quebec. Pooled risk estimates, relating to 44,925 children, yielded expected gradients (income: low 1.83(CI 1.38,2.41), middle 1.42(1.13,1.79), high (reference); maternal education: low 2.13(1.39,3.25), middle 1.42(1.13,1.79)). Estimates of absolute inequality using SII showed that the largest differences in ADHD prevalence between the highest and lowest levels of maternal education were observed in Australia (4% lower) and Sweden (3% lower); for household income, the largest differences were observed in Quebec (6% lower) and Canada (all provinces: 5% lower). Conclusion: Findings indicate that children in families with high household income or maternal education are less likely to have ADHD at age 9–11. Absolute inequality, in combination with relative inequality, provides a more complete account of the socioeconomic status and ADHD relationship in different high-income countries. While the study design precludes causal inference, the linear relation between early childhood social circumstances and later ADHD suggests a potential role for policies that promote high levels of education, especially among women, and adequate levels of household income over children’s early years in reducing risk of later ADHD

Social Inequalities in Child Health : Type 1 Diabetes, Obesity, Cardiovascular Risk Factors and the Role of Self-control

The Swedish Commission on Health Inequality defined health inequality as systematic differences in health between groups in society with different social positions. All avoidable socioeconomic health inequalities are unfair, and as stated by WHO's Commission on the Social Determinants of Health, we have a moral obligation to try to reduce them. "Putting these inequities right is a matter of social justice. Reducing health inequities is, for the Commission on Social Determinants of Health, an ethical imperative." This ethical imperative is especially apparent regarding the health of children and adolescents. Children’s right to the highest attainable standard of health is also enshrined in Article 24 of the Convention on the Rights of the Child. To reach the goal of a reduction of health inequalities, research is necessary to describe the social gradients of health. Research is also needed to better understand why these gradients occur. A better understanding and knowledge about health inequalities can lead to policies that reduce these inequalities and ensure children’s right to health. This thesis investigates social inequality in child health using data from a Swedish population-based prospective birth cohort, the All Babies in Southeast Sweden (ABIS) cohort. Social inequality in obesity in the ABIS cohort is also compared with other birth cohorts participating in the Elucidating Pathways to Child Health Inequality (EPOCH) collaboration which includes cohorts from six high-income countries; Sweden, the Netherlands, Canada (one national and one cohort from Quebec), UK, Australia, and USA. In Paper 1 we show that health inequalities in overweight and obesity are detectable already at two years of age and that these inequalities increase during childhood. In adolescents, low socioeconomic status increases the risk of becoming overweight and the risk of components of the metabolic syndrome, including high blood pressure and dyslipidemia (low high-density cholesterol). The level of inequality in obesity in the Swedish ABIS cohort was lower than in the other participating countries in the EPOCH collaboration (Paper 2). Inequality was lower in absolute and relative terms when SES was measured by household income. Inequality was also lower in absolute, but not relative, terms when SES was measured by maternal education. This finding indicates that some of the policies implemented in Sweden may attenuate social inequalities in obesity in children. Examples of such policies with evidence for reducing social inequality in obesity implemented in Sweden include universal preschools and free school meals. This thesis also investigates health inequalities in autoimmune disease (Paper 3). In this study, we found that low socioeconomic status increased the risk of Type 1 Diabetes but not the other autoimmune diseases investigated. Path analysis indicated that part of the increased risk in children with low SES of Type 1 Diabetes might be mediated by a higher body mass index and an elevated risk of serious life events. In the final paper, this thesis tests the hypothesis that differences in maternal and child self-control mediate social inequalities in obesity. Two measures of self-control were used; for mothers, the self-control variable was based on behaviors related to self-control (smoking during pregnancy, smoking during the child’s first year of life, breastfeeding duration, and participating in the ABIS study with biological samples). For the children, the self-control variable was based on questionnaire data on the impulsivity subscale of the Strengths and Difficulties Questionnaire (SDQ). The results showed that the two measures of self-control mediated 87.5 % of the increased risk of obesity at age 19 years in children with low maternal education and 93 % of the risk if maternal BMI was also included in the selfcontrol variable. In the discussion part of this thesis, the conclusions that can be deduced from understanding the mechanisms of social inequality in child health are discussed. A theory with a central role of self-control for health inequality predicts that social inequality will increase without interventions. In an environment with rising numbers of stimuli of the human reward system, stimuli that also have negative long-term consequences (socalled Limbic traps), child and adolescent health, in general, will decrease. Because of the mechanisms related to SES and self-control, children with low SES will be disproportionally affected. The result of this development will be increasing levels of social inequalities in child health. The discussion also includes implications for policies that may improve health and reduce inequalities. These policies should reduce the exposure of children and adolescents to harmful behaviors/limbic traps. Examples of policies that have this effect include universal preschools for all children, free healthy meals in preschools and schools, increased after-school activities for all children, and longer school days for adolescents with increased hours for physical activity, music, and art. Mobile phones and social media restrictions in schools and policies to reduce use at home should also be implemented. Finally, policies should be implemented to reduce residential and school segregation in the community.Hälsoojämlikhet definierades av den Svenska kommissionen för jämlik hälsa som "systematiska skillnader i hälsa mellan samhällsgrupper med olika social position." Debatten om de bakomliggande orsakerna till hälsoojämlikhet tog fart efter att rapporten "the Black Report" kom ut i Storbritannien på 1980-talet. I denna rapport konstaterades att ojämlikheten i hälsa hade ökat mellan socioekonomiska grupper trots införandet av fri sjukvård och andra samhällsförbättringar. Orsakerna till den ökande ojämlikheten har sedan dess debatterats och ett antal teorier har lagts fram för att förklara fenomenet. Fortfarande råder det dock oenighet kring hur de olika bakomliggande faktorerna leder fram till skillnaderna i hälsa. Internationella organisationer har samtidigt arbetat för att minska skillnaderna, bland annat WHO som 2008 bildades "the Commission on Social Determinants of Health". Denna kommission slog fast i sin rapport att vi alla har en moralisk plikt att minska skillnaderna i hälsa; "Att ställa dessa skillnader till rätta handlar om social rättvisa. Att minska hälsoojämlikhet är för kommissionen ett etiskt imperativ". Rätten till bästa möjliga hälsa slås också fast i Barnkonventionen, artikel 24. För att kunna minska hälsoojämlikheter behöver man studera inom vilka områden/sjukdomar skillnader uppstår och varför, med målet att utforma åtgärder för att minska skillnaderna. Denna avhandling syftar till att studera socioekonomiska skillnader i barns hälsa. Avhandlingen baseras på data från den svenska prospektiva födelsekohortstudien Alla Barn i Sydöstra Sverige (ABIS). Social ojämlikhet i övervikt och obesitas jämförs även med den sociala ojämlikheten i motsvarande data från födelsekohorter i fem andra höginkomstländer; Nederländerna, Kanada, Storbritannien, Australien och USA. Resultaten från Studie 1 visade att socioekonomiska skillnader i risken att utveckla obesitas kan upptäckas redan vid 2 års ålder och att denna skillnad i risk ökade under uppväxten. I tonåren framkom socioekonomiska skillnader gällande övervikt/obesitas samt för utvecklingen av högt blodtryck och lågt HDL-kolesterol (delar av det metabola syndromet). Socioekonomisk ojämlikhet i förekomsten av obesitas i ABIS var mindre än i de övriga kohorterna i EPOCH-samarbetet (Studie 2). Detta gällde både i absoluta och relativa mått när socioekonomisk status mättes med hushållsinkomst. När socioekonomisk status baserades på moderns utbildningsnivå var skillnaderna mindre i ABIS i absoluta men inte i relativa mått. Fynden tyder på att samhällspolitiska åtgärder i Sverige tycks minska ojämlikhet i obesitas under barnaåren. Subventionerad förskola och gratis skolmat i förskola och skola är exempel på åtgärder som visat sig ha en effekt på socioekonomiska skillnader i obesitas. Vi har även studerat socioekonomiska skillnader i risk att utveckla autoimmuna sjukdomar (studie 3). Typ 1 Diabetes visade sig vara mer vanligt förekommande hos barn vars mödrar enbart hade förgymnasial utbildning. Denna skillnad kunde delvis förklaras av ett i genomsnitt högre BMI under barndomen och en ökad risk för allvarliga livshändelser i denna grupp. För övriga studerade autoimmuna sjukdomar fanns inga statistiskt signifikanta socioekonomiska skillnader. I avhandlingens sista studie prövades hypotesen att den sociala ojämlikheten (mätt med moderns utbildningsnivå) och risken att utveckla obesitas medierades av skillnader i självkontroll hos mor och barn. Självkontroll hos modern estimerades genom följande beteendevariabler; rökning under graviditeten, rökning under barnets första levnadsår, amningsduration och grad av deltagande i ABIS-studiens datainsamling med biologisk provtagning. Barnets grad av självkontroll uppskattades genom analys av svar i frågeformuläret SDQs subskala om impulsivitet. Resultatet av studien visade att mor och barns självkontroll medierade 87,5 % av sambandet mellan moderns utbildningsnivå och barnets risk att ha utvecklat obesitas vid 19 års ålder. Sambandet stärktes ytterligare om även moderns BMI vid barnets 1 års ålder adderades till analysen. Den medierade effekten ökade då till 93 % av den totala. En av avhandlingens slutsatser är att begreppet självkontroll bör ha en central roll i teorin om hälsoojämlikhetens orsaker. En sådan teori förutser att hälsoojämlikheten kommer att öka succesivt om inga interventioner görs. Hälsan hos barn och ungdomar kommer påverkas negativt av en miljö med ökande tillgång till allt fler stimuli av hjärnans belöningssystem, stimuli vilka också har negativa långtidseffekter för hälsan (s.k. Limbiska fällor ex. sociala medier). På grund av kopplingen mellan socioekonomisk status och självkontroll, kommer barn med låg socioekonomisk status drabbas i högre uträckning av denna ohälsa vilket kommer att leda till ökad hälsoojämlikhet. Slutligen diskuteras vilka implikationer för hälso- och sjukvården, liksom för hälsopolitiken, som resultaten i avhandlingen kan få och hur man kan minska den sociala ojämlikheten i hälsa. Sådana hälsopolitiska åtgärder bör reducera barn och ungdomars risk för skadliga beteenden/limbiska fällor. Exempel på åtgärder inkluderar förskola för alla barn (oavsett om föräldrarna yrkesarbetar eller ej), fria hälsosamma måltider i förskola och skola, ökad möjlighet till aktiviteter efter skoltid, förlängda skoldagar för äldre barn med mer skolgymnastik, musik och estetiska ämnen, restriktioner för mobilanvändning för att motverka överanvändande av mobiltelefoner i hemmet och skolan, samt policys för att motverka boende och skolsegregation i samhället

Toxic metals in cord blood and later development of Type 1 diabetes.

The incidence of type 1 diabetes (T1D) has increased explained by changes in environment or lifestyle. In modern society dissemination of heavy metals has increased. As the autoimmune process usually starts already, we hypothesized that exposure to toxic metals during fetal life might contribute to development of T1D in children. We analysed arsenic (AS), aluminium (Al), cadmium (Cd), lithium (Li), mercury (Hg), lead (Pb), in cord blood of 20 children who later developed T1D (probands), and in 40 age-and sex-matched controls. Analysis of heavy metals in cord blood was performed by ALS Scandinavia AB (Luleå, Sweden) using the 'ultrasensitive inductively coupled plasma sector field mass spectrometry method' (ICP-SFMS) after acid digestion with HNO3. Most children had no increased concentrations of the metals in cord blood. However, children who later developed T1D had more often increased concentrations (above limit of detection; LOD) of aluminium (p = 0.006) in cord blood than the non-diabetic controls, and also more often mercury and arsenic (n.s). Our conclusion is that exposure to toxic metals during pregnancy might be one among several contributing environmental factors to the disease process if confirmed in other birth cohort trials

Low maternal education increases the risk of Type 1 Diabetes, but not other autoimmune diseases: a mediating role of childhood BMI and exposure to serious life events

The objective of this paper was to investigate if socioeconomic status (SES), measured by maternal education and household income, influenced the risk of developing autoimmune disease (Type 1 Diabetes, Celiac disease, Juvenile Idiopathic Arthritis, Crohns disease, Ulcerative colitis, and autoimmune thyroid disease), or age at diagnosis, and to analyse pathways between SES and autoimmune disease. We used data from the All Babies in Southeast Sweden (ABIS) study, a population-based prospective birth cohort, which included children born 1997-1999. Diagnoses of autoimmune disease was collected from the Swedish National Patient Register Dec 2020. In 16,365 individuals, low maternal education, but not household income, was associated with increased risk of Type 1 Diabetes; middle education RR 1.54, 95% CI 1.06, 2.23; P 0.02, low education RR 1.81, 95% CI 1.04, 3.18; P 0.04. Maternal education and household income was not associated with any other autoimmune disease and did not influence the age at diagnosis. Part of the increased risk of Type 1 Diabetes by lower maternal education was mediated by the indirect pathway of higher BMI and higher risk of Serious Life Events (SLE) at 5 years of age. The risk of developing Type 1 Diabetes associated to low maternal education might be reduced by decreasing BMI and SLE during childhood.Funding Agencies|Linkoeping University; County Council of Ostergot-land, Forskningsradet i Sydoestra Sverige, Vetenskapsradet [K2005-72X-11242-11A]; Knut och Alice Wallenbergs Stiftelse [K 98-99D-12813-01A]; Forskningsradet foer Arbetsliv och Socialvetenskap [FAS20041775]; Barndiabetesfonden; Juvenile Diabetes Research Foundation International; Ostgota Brandstodsbolag</p

Inequalities in cardiovascular risks among Swedish adolescents (ABIS): a prospective cohort study

Objectives To investigate if socioeconomic status (SES) is predictive of cardiovascular risk factors among Swedish adolescents. Identify the most important SES variable for the development of each cardiovascular risk factor. Investigate at what age SES inequality in overweight and obesity occurs. Design Longitudinal follow-up of a prospective birth cohort. Setting All Babies in Southeast Sweden (ABIS) study includes data from children born between October 1997 and October 1999 in five counties of south east Sweden. Participants A regional ABIS-study subsample from three major cities of the region n=298 adolescents aged 16-18 years, and prospective data from the whole ABIS cohort for overweight and obesity status at the ages 2, 5, 8 and 12 years (n=2998-7925). Outcome measures Blood pressure above the hypertension limit, overweight/obesity according to the International Obesity Task Force definition, low high-density lipoproteins (HDL) or borderline-high low-density lipoproteins according to National Cholesterol Education Program expert panel on cholesterol levels in children. Results For three out of four cardiovascular risk outcomes (elevated blood pressure, low HDL and overweight/obesity), there were increased risk in one or more of the low SES groups (p&amp;lt;0.05). The best predictor was parental occupational class (Swedish socioeconomic classification index) for elevated blood pressure (area under the receiver operating characteristic (ROC) curve 0.623), maternal educational level for overweight (area under the ROC curve 0.641) and blue-collar city of residence for low HDL (area under the ROC curve 0.641). SES-related differences in overweight/obesity were found at age 2, 5 and 12 and for obesity at age 2, 5, 8 and 12 years (all p&amp;lt;0.05). Conclusions Even in a welfare state like Sweden, SES inequalities in cardiovascular risks are evident already in childhood and adolescence. Intervention programmes to reduce cardiovascular risk based on social inequality should start early in life.Funding Agencies|Swedish Research CouncilSwedish Research Council [K2005-72X-11242-11A, K2008-69X-20826-01-4]; Swedish Child Diabetes Foundation (Barndiabetesfonden); JDRF Wallenberg Foundation [K 98-99D-12813-01A]; Medical Research Council of Southeast Sweden (FORSS); Swedish Council for Working Life and Social ResearchSwedish Research CouncilSwedish Research Council for Health Working Life &amp; Welfare (Forte) [FAS2004-1775]; Ostgota Brandstodsbolag; Research and PhD studies Committee (FUN), Linkoping University, Sweden (LiU-)</p

Household income and maternal education in early childhood and activity-limiting chronic health conditions in late childhood : findings from birth cohort studies from six countries

We examined absolute and relative relationships between household income and maternal education during early childhood (<5 years) with activity-limiting chronic health conditions (ALCHC) during later childhood in six longitudinal, prospective cohorts from high-income countries (UK, Australia, Canada, Sweden, Netherlands, USA). Relative inequality (risk ratios, RR) and absolute inequality (Slope Index of Inequality) were estimated for ALCHC during later childhood by maternal education categories and household income quintiles in early childhood. Estimates were adjusted for mother ethnicity, maternal age at birth, child sex and multiple births, and were pooled using meta-regression. Pooled estimates, with over 42 000 children, demonstrated social gradients in ALCHC for high maternal education versus low (RR 1.54, 95% CI 1.28 to 1.85) and middle education (RR 1.24, 95% CI 1.11 to 1.38); as well as for high household income versus lowest (RR 1.90, 95% CI 1.66 to 2.18) and middle quintiles (RR 1.34, 95% CI 1.17 to 1.54). Absolute inequality showed decreasing ALCHC in all cohorts from low to high education (range: -2.85% Sweden, -13.36% Canada) and income (range: -1.8% Sweden, -19.35% Netherlands). We found graded relative risk of ALCHC during later childhood by maternal education and household income during early childhood in all cohorts. Absolute differences in ALCHC were consistently observed between the highest and lowest maternal education and household income levels across cohort populations. Our results support a potential role for generous, universal financial and childcare policies for families during early childhood in reducing the prevalence of activity limiting chronic conditions in later childhood. [Abstract copyright: © Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.

Household income and maternal education in early childhood and risk of overweight and obesity in late childhood : findings from seven birth cohort studies in six high-income countries.

This study analysed the relationship between early childhood socioeconomic status (SES) measured by maternal education and household income and the subsequent development of childhood overweight and obesity. Data from seven population-representative prospective child cohorts in six high-income countries: United Kingdom, Australia, the Netherlands, Canada (one national cohort and one from the province of Quebec), USA, Sweden. Children were included at birth or within the first 2 years of life. Pooled estimates relate to a total of N = 26,565 included children. Overweight and obesity were defined using International Obesity Task Force (IOTF) cut-offs and measured in late childhood (8-11 years). Risk ratios (RRs) and pooled risk estimates were adjusted for potential confounders (maternal age, ethnicity, child sex). Slope Indexes of Inequality (SII) were estimated to quantify absolute inequality for maternal education and household income. Prevalence ranged from 15.0% overweight and 2.4% obese in the Swedish cohort to 37.6% overweight and 15.8% obese in the US cohort. Overall, across cohorts, social gradients were observed for risk of obesity for both low maternal education (pooled RR: 2.99, 95% CI: 2.07, 4.31) and low household income (pooled RR: 2.69, 95% CI: 1.68, 4.30); between-cohort heterogeneity ranged from negligible to moderate (p: 0.300 to < 0.001). The association between RRs of obesity by income was lowest in Sweden than in other cohorts. There was a social gradient by maternal education on the risk of childhood obesity in all included cohorts. The SES associations measured by income were more heterogeneous and differed between Sweden versus the other national cohorts; these findings may be attributable to policy differences, including preschool policies, maternity leave, a ban on advertising to children, and universal free school meals. [Abstract copyright: © 2022. The Author(s).