Lifetime exposure to air pollution and academic achievement: A nationwide cohort study in Denmark.

Recent research suggests a link between air pollution and cognitive development in children, and studies on air pollution and academic achievement are emerging. We conducted a nationwide cohort study in Denmark to explore the associations between lifetime exposure to air pollution and academic performance in 9th grade. The study encompassed 785,312 children born in Denmark between 1989 and 2005, all of whom completed 9th-grade exit examinations. Using linear mixed models with a random intercept for each school, we assessed the relationship between 16 years of exposure to PM2.5, PM10, and gaseous pollutants and Grade Point Averages (GPA) in exit examinations, covering subjects such as Danish literature, Danish writing, English, mathematics, and natural sciences. The study revealed that a 5 µg/m3 increase in PM2.5 and PM10 was associated with a decrease of 0.99 (95 % Confidence Intervals: -1.05, -0.92) and 0.46 (-0.50, -0.41) in GPA, respectively. Notably, these negative associations were more pronounced in mathematics and natural sciences compared to language-related subjects. Additionally, girls and children with non-Danish mothers were found to be particularly susceptible to the adverse effects of air pollution exposure. These results underscore the potential long-term consequences of air pollution on academic achievement, emphasizing the significance of interventions that foster healthier environments for children's cognitive development.

Air pollution and human health: a phenome-wide association study.

OBJECTIVES: To explore the associations of long-term exposure to air pollution with onset of all human health conditions. DESIGN: Prospective phenome-wide association study. SETTING: Denmark. PARTICIPANTS: All Danish residents aged ≥30 years on 1 January 2000 were included (N=3 323 612). After exclusion of individuals with missing geocoded residential addresses, 3 111 988 participants were available for the statistical analyses. MAIN OUTCOME MEASURE: First registered diagnosis of every health condition according to the International Classification of Diseases, 10th revision, from 2000 to 2017. RESULTS: Long-term exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) were both positively associated with the onset of more than 700 health conditions (ie, >80% of the registered health conditions) after correction for multiple testing, while the remaining associations were inverse or insignificant. As regards the most common health conditions, PM2.5 and NO2 were strongest positively associated with chronic obstructive pulmonary disease (PM2.5: HR 1.06 (95% CI 1.05 to 1.07) per 1 IQR increase in exposure level; NO2: 1.14 (95% CI 1.12 to 1.15)), type 2 diabetes (PM2.5: 1.06 (95% CI 1.05 to 1.06); NO2: 1.12 (95% CI 1.10 to 1.13)) and ischaemic heart disease (PM2.5: 1.05 (95% CI 1.04 to 1.05); NO2: 1.11 (95% CI 1.09 to 1.12)). Furthermore, PM2.5 and NO2 were both positively associated with so far unexplored, but highly prevalent outcomes relevant to public health, including senile cataract, hearing loss and urinary tract infection. CONCLUSIONS: The findings of this study suggest that air pollution has a more extensive impact on human health than previously known. However, as this study is the first of its kind to investigate the associations of long-term exposure to air pollution with onset of all human health conditions, further research is needed to replicate the study findings.

Satisfaction with life and SF-36 vitality predict risk of ischemic heart disease: a prospective cohort study.

The main objective of the current study was to investigate associations between two aspects of well-being - satisfaction with life and vitality - and incidence of and mortality from ischemic heart disease. Study design. The Copenhagen Aging and Midlife Biobank (CAMB) was conducted from 2009 to 2011 and was used as baseline data with 6750 individuals having complete information on The Satisfaction with Life Scale (SWLS) and 6652 individuals with complete information on the Short Form Health Survey (SF-36) vitality scale. Incidence of and mortality from ischemic heart disease were assessed using Danish register data and a total of 349 CAMB individuals were registered with either a diagnosis (n = 337) or had died (n = 12) from ischemic heart disease before the end of follow-up (31 December 2017). The hazard ratios of ischemic heart disease according to satisfaction with life and vitality scores were investigated using Cox proportional hazard regression adjusted for potential covariates. Results. A one standard deviation increase on the SWLS was associated with an 18% reduced risk of ischemic heart disease while a one standard deviation increase on the SF-36 vitality scale was associated with a 24% reduced risk of ischemic heart disease after adjustment for baseline socio-demographic factors. These associations remained when separately adjusting for lifestyle, objective health, and social factors, but became non-significant when adjusting for self-reported health. Conclusion. Our study indicates that both psychological and health-related components of wellbeing are important in relation to ischemic heart disease.

Does meaning protect against loneliness? Exploring empirical studies and theory.

Research indicates that meaning in life is a protective factor for physical and mental health. Although loneliness is increasingly recognized as an important public health concern, no studies have investigated the potential of meaning in life to protect against loneliness. Based on an explorative interdisciplinary research strategy that comprises data from a cohort study, a strategic review of empirical literature and a conceptual analysis of the concept of meaning in life we explore the support for potential links between meaning in life and the protection against loneliness. We propose three different explanatory mechanisms; (i) that meaning in life promotes a positive orientation toward others, (ii) that meaning in life enhances interpersonal appeal and (iii) that meaning in life promotes a better ability to cope with loneliness. Theoretically, we explore the idea that the value of meaning in life ultimately concerns a social need to contribute to the realization of value that, at least in principle, can be shared and recognized by others. When people realize the value of meaning in life, they partake in a community of shared values, which links them to a social world in a way that may protect against the feeling of loneliness. Jointly the analyses point to the need for prospective studies on the role of meaning in life as a protective factor against loneliness and a potential novel focus for loneliness interventions.

The Moderating Influence of School Achievement on Intelligence in Young Adulthood.

Education has been suggested to be possibly the most consistent, robust, and durable method available for raising intelligence, but little is known about the genetic and environmental interplay underlying this association. Therefore, we investigated how school achievement, as measured by grade point average in lower secondary school at 15 years of age, moderated intelligence variation in young adulthood. The sample consisted of all Danish male twin pairs who had left lower secondary school since 2002 and appeared, typically at age 18, before a draft board through 2015 (N = 2660). Shared environmental variance unique to intelligence (10% of total variance) was found to be greater among individuals with poor school achievement. However, school achievement did not moderate the genetic influences or the non-shared environmental influences on intelligence. We discuss the implications of this in light of the constraints imposed by the statistical models we used.

Birth weight and quality of life in midlife: a 50-year follow-up study of 2079 individuals in Denmark.

PURPOSE: Low birth weight has been associated with a higher risk of reduced quality of life (QoL) in children, adolescents, and young adults, but the influence seems to diminish over time. However, previous studies have mainly focused on health-related QoL and compared individuals with low birth weight with individuals without low birth weight. The purpose of the present cohort study was to investigate the influence of the entire range of birth weights on three distinct measures of QoL in midlife. METHODS: The study population consisted of all live-born singletons from the Copenhagen Perinatal Cohort (CPC, 1959-1961) who participated in a 50-year follow-up examination in 2009-2011 (N = 2079). Birth weight was measured by three pediatricians at birth. QoL was measured at the follow-up by the participants' scores on three QoL self-report measures: The Satisfaction With Life Scale, the Vitality Scale of the Medical Outcomes Study 36-Item Short-Form Health Survey, and a single-item QoL measure based on the question: "How is your quality of life at the moment?". General linear regression and binary logistic regression were used to estimate the association between birth weight and QoL in midlife. RESULTS: Small, curvilinear associations of birth weight with life satisfaction, vitality, and the single-item QoL measure were found, suggesting that both low and high birth weights increase the risk of low satisfaction with life, low vitality and low QoL. CONCLUSION: The study findings suggest that low and high-range birth weight exert a lasting influence on distinct, but complementary aspects of QoL in midlife.

Educational Attainment and Pregnancy Outcomes: A Danish Register-Based Study of the Influence of Childhood Social Disadvantage on Later Socioeconomic Disparities in Induced Abortion, Spontaneous Abortion, Stillbirth and Preterm Delivery.

Objectives Socioeconomic disparities in pregnancy outcomes have been found across times and places, but there is a lack of studies investigating the underlying causes. The present study investigated the influence of child protective services in the pregnant woman's family of origin as a proxy of childhood social disadvantage. Methods The study population comprised all registered pregnancies in Denmark during the period from 2000 to 2009 that resulted in an induced abortion, spontaneous abortion, stillbirth or live birth (N = 786,054). Linear regression was used to analyze the associations between educational attainment and pregnancy outcomes in models with and without adjustment for age, parental educational attainment and child protective services in the family of origin. Further, it was tested whether child protective services in the pregnant woman's family of origin modified the associations between educational attainment and pregnancy outcomes. Results Women with low educational attainment had a higher risk of induced abortion, stillbirth and preterm delivery and a lower risk of spontaneous abortion. These associations were to some extent explained by child protective services in the family of origin. Further, child protective services in the pregnant woman's family of origin modified the association between educational attainment and risk of preterm delivery. Thus, women with high educational attainment were not found to differ in risk of preterm delivery according to child protective services in the family of origin Conclusions for Practice Information on childhood social disadvantage may enrich our understanding of the socioeconomic disparities in pregnancy outcomes.

Parental socioeconomic position and risk of ADHD in offspring: a cohort study of 9648 individuals in Denmark 1976-2013.

The strength of the association between parental socioeconomic position (SEP) and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring is found to vary substantially, perhaps due to the negligence of possible changes in parental life course SEP. The present study investigated the association between parental SEP in adulthood and risk of ADHD diagnosis in offspring and whether parental childhood SEP modified this association. The study population included 9648 live-born singletons followed in the Psychiatric Central Register from birth in 1976-1996 until 2013. Cox regression was used to estimate hazard ratios for ADHD diagnosis according to parental SEP in adulthood. The results showed that low parental SEP in adulthood was associated with higher risk of ADHD diagnosis in offspring, also after adjustment for possible confounders. Thus, offspring of parents with low SEP in adulthood had 4.52 (95% CI 2.81-7.26) times higher hazard of ADHD diagnosis compared with offspring of parents with high SEP in adulthood. Further, parental childhood SEP was found to modify the observed association. Thus, offspring of parents with downward social mobility from childhood to adulthood and offspring of parents with stable low SEP experienced the highest risk of ADHD diagnosis, followed by offspring of parents with upward social mobility, compared with offspring of parents with stable high SEP. The results suggest that it is important to take into account the possibility of social mobility as changes in parental life course SEP from childhood to adulthood seem to influence the risk of ADHD diagnosis in offspring.

The association between life satisfaction, vitality, self-rated health, and risk of cancer.

PURPOSE: Only few prospective studies have been conducted on the contribution of quality of life-related factors to the risk of cancer. The aim of this study was to investigate the prospective associations of three quality of life-related factors with the risk of cancer; life satisfaction, vitality, and self-rated health. METHODS: In 2009-2011, 7189 participants in the Copenhagen Aging and Midlife Biobank were asked to rate their life satisfaction, their vitality, and their health. The study population was followed until the end of 2015 for registration of cancer in the Danish National Patient Register. RESULTS: During the follow-up period, cancer was diagnosed in 312 individuals. Life satisfaction was not associated with the risk of cancer. Vitality was significantly associated with the risk of cancer, but the association became non-significant after adjustment for age, sex, socioeconomic position, and lifestyle factors. However, when additionally adjusting for life satisfaction, individuals who rated their vitality as low had a hazard ratio of 1.46 (95% confidence interval [CI] 1.04-2.07) for the development of cancer. Individuals who rated their health as poor had a hazard ratio of 1.70 (95% CI 1.27-2.26) for the development of cancer, compared with individuals with good, very good, or excellent self-rated health. The association remained significant after adjustment for basic confounders, life satisfaction, and vitality. CONCLUSION: A better grasp of the significance of quality of life-related factors for the risk of cancer may be of great importance to population-based cancer prevention that aims to target early risk factors for development of cancer across widespread cancer sites.

Prospective Associations of the Short Form Health Survey Vitality Scale and Changes in Body Mass Index and Obesity Status.

Objectives: The objectives of the current study were to prospectively investigate the predictive value of the vitality scale of the Short Form Health Survey for changes in body mass index and development of obesity. Methods: The study population comprised 2864 (81.5%) men and 648 (18.5%) women from the Metropolit Project and the Danish Longitudinal Study on Work, Unemployment and Health, who participated in a follow-up examination in 2009-2011 corresponding to a follow-up period of 3-7 years. Associations of vitality with body mass index and obesity were investigated separately for men and women in linear and logistic regression models adjusting for age, baseline body mass index, education, physical activity, smoking, and obesity-related diseases. Results: Vitality was significantly associated with change in body mass index among men (p < 0.001) and women (p < 0.05) gaining weight after adjusting for age, baseline body mass index, education, physical activity, smoking, and obesity-related diseases. No significant associations of vitality with BMI change were observed among individuals maintaining or losing weight during the follow-up period. Furthermore, vitality significantly predicted development of obesity among women. Conclusion: The study indicates that vitality is of predictive value for increases in BMI over time among individuals gaining weight and may further predict the development of obesity among women. This identification of poor vitality as a potential risk indicator for weight gain and development of obesity may be beneficial in clinical practice.

Interpregnancy Interval and Risk of Adverse Pregnancy Outcomes: A Register-Based Study of 328,577 Pregnancies in Denmark 1994-2010.

Objectives To investigate the associations of interpregnancy interval (IPI) with miscarriage, stillbirth, preterm delivery and small for gestational age delivery. Methods The study population comprised all women who had a live birth and at least one subsequent pregnancy in Denmark during the period from 1994 to 2010 (N = 328,577). Linear regression was used to estimate risk differences for miscarriage, stillbirth, preterm delivery and small for gestational age delivery according to IPI. Results The results were heterogeneous: the risk of miscarriage increased monotonically with the length of the IPI. Compared to women with IPIs of 18-23 months, women with IPIs of 0-5 months experienced 18.7 (13.1-24.2) fewer miscarriages per 1000 pregnancies, while women with IPIs of ≥ 60 months experienced 28.7 (23.4-34.0) more miscarriages per 1000 pregnancies. We found that women with IPIs of ≥ 60 months had 1.7 (0.4-3.0) more stillbirths per 1000 births compared to women with IPIs of 18-23 months. U-shaped associations were seen for preterm delivery and small for gestational age delivery with women with IPIs of 18-23 months experiencing the lowest risks of these outcomes. Conclusions for Practice The heterogeneity in associations between IPI and adverse pregnancy outcomes suggests that different mechanisms of action may be at play at various times in the antepartum period. While the finding for miscarriage suggests that fecundity is an important determinant for IPI, the findings for preterm delivery and small for gestational age delivery suggest the coexistence of the maternal depletion syndrome mechanism and the physiological regression mechanism and the finding for stillbirth speaks against a strict maternal depletion syndrome explanation.