| 1. |
- Barclay, Kieron, 1986-, et al.
(författare)
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Birth Order and Physical Fitness in Early Adulthood : Evidence from Swedish Military Conscription Data
- 2014
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Ingår i: Social Science and Medicine. - : Elsevier. - 0277-9536 .- 1873-5347. ; 123, s. 141-148
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Tidskriftsartikel (refereegranskat)abstract
- Physical fitness at young adult ages is an important determinant of physical health, cognitive ability, and mortality. However, few studies have addressed the relationship between early life conditions and physical fitness in adulthood. An important potential factor influencing physical fitness is birth order, which prior studies associate with several early- and later-life outcomes such as height and mortality. This is the first study to analyse the association between birth order and physical fitness in late adolescence. We use military conscription data on 218,873 Swedish males born between 1965 and 1977. Physical fitness is measured by a test of maximal working capacity, a measure of cardiovascular fitness closely related to V02max. We use linear regression with sibling fixed effects, meaning a within-family comparison, to eliminate the confounding influence of unobserved factors that vary between siblings. To understand the mechanism we further analyse whether the association between birth order and physical fitness varies by sibship size, parental socioeconomic status, birth cohort or length of the birth interval. We find a strong, negative and monotonic relationship between birth order and physical fitness. For example, third-born children have a maximal working capacity approximately 0.1 (p<0.000) standard deviations lower than first-born children. The association exists both in small (3 or less children) and large families (4 or more children), in high and low socioeconomic status families, and amongst cohorts born in the 1960s and the 1970s. While in the whole population the birth order effect does not depend on the length of the birth intervals, in two-child families a longer birth interval strengthens the advantage of the first-born. Our results illustrate the importance of birth order on physical fitness, and suggest that the first-born advantage already arises in late adolescence.
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| 2. |
- Barclay, Kieron J., et al.
(författare)
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Peer clustering of exercise and eating behaviours among young adults in Sweden : a cross-sectional study of egocentric network data
- 2013
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Ingår i: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 13, s. 784-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Research suggests that the growing prevalence of obesity may be related to the influence of the health behaviours of peers. We look at clustering of exercise and eating behaviours amongst a previously unstudied group, young adults in Sweden. Previous research has mainly been conducted in the United States and Britain, countries that have relatively high rates of obesity. Methods: Using ego-alter dyads from the egocentric network data as the unit of analysis, we conduct logistic regressions to investigate the association between ego and alter exercise and eating behaviours. Results: Respondents have a significantly greater probability of engaging in regular exercise and eating healthily if a nominated peer also does so. Furthermore, the degree to which this behavior is shared is modulated by the strength of the relationship between the two individuals, with a greater probability of engaging in these behaviours observed when the relationship with the nominated peer is strong relative to when the relationship is weak. However, we find that ego-alter homogeneity in terms of gender and migration status was not associated with a significantly greater probability of behaving in a similar manner to a nominated peer. Furthermore, the status of the nominated peer as a relative or not did not impact the probability that the ego would engage in similar health behaviours to that alter. Conclusions: We observe strong associations between ego and alter health behaviours for young adults, consistent with previous research. Although we cannot draw causal inferences, these results suggest that the health behaviours of an individual's peers may play a role in shaping their own health behaviours.
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| 3. |
- Barclay, Kieron J.
(författare)
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SEX COMPOSITION OF THE WORKPLACE AND MORTALITY RISK
- 2013
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Ingår i: Journal of Biosocial Science. - 0021-9320 .- 1469-7599. ; 45:6, s. 807-821
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Tidskriftsartikel (refereegranskat)abstract
- This study uses Swedish occupational register data to examine whether the proportion of men in administrative workplaces in the Swedish public service affects all-cause mortality risks amongst both males and females of working age. Using piecewise constant survival models to analyse occupational data from the Swedish administrative registers from 1995 to 2007, it was found that for males, a 1% increase in the proportion of males was associated with a 1.3% increase in mortality risk (hazard ratio, HR 1.013, 95% CI 1.007-1.020, p < 0.001), but no association was found for females (HR 1.004, 95% CI 0.996-1.012, p = 0.297). Adjustments were made for age, family status, education, occupational status, occupational segregation by sex, the total number of individuals in the workplace, level of government, region, period and variables reflecting the workplace structure by age, age by sex, occupation and education. A higher proportion of males may be related to (i) an increased exposure to risky health behaviours such as alcohol consumption and unhealthy dietary patterns, (ii) a tendency towards sickness presenteeism, and (iii) an increase in the levels of several well-established emotional stressors in the workplace, leading to an increased level of psychosocial stress. The findings and potential extensions of this research are discussed.
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| 4. |
- Barclay, Kieron J.
(författare)
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Sex ratios at sexual maturity and longevity : Evidence from Swedish register data
- 2013
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Ingår i: Demographic Research. - 1435-9871. ; 29, s. 837-864
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study tests the recently proposed hypothesis that the contextual sex ratio at sexual maturity is related to longevity. Previous empirical research in the United States has shown that a higher proportion of males at the age of sexual maturity increases the risk of mortality for males both before and after the age of 65.Methods: I use Swedish administrative register data, linking the 1960 census to individual- level mortality data over the period 1960 to 2007. I calculate the sex ratio at two geographic levels, municipalities and parishes. Two different specifications of the sex ratio are calculated: males aged 18 to 27 over females aged 15 to 24, and males aged 18 to 22 over females aged 16 to 20. I conduct piece-wise constant survival analyses over the period from 1960 to 2007 to analyze the risk of mortality before age 65. I run separate analyses for males and females, using cohorts born in 1941 and 1942.Results: For males, the results generally show that for both males and females a higher proportion of males was associated with a lower relative risk of mortality before age 65. The results were not statistically significant.Conclusions: The lack of a consistent statistically significant association for either males or females, and the trend for males being in the opposite direction of what was hypothesized, suggests that support for the hypothesis in Sweden is very weak.
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| 5. |
- Barclay, Kieron J., et al.
(författare)
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Workplace sex composition and ischaemic heart disease : A longitudinal analysis using Swedish register data
- 2014
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 42:6, s. 525-533
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The aim of this study is to follow-up on previous research indicating that the sex composition of workplaces is related to a number of health outcomes, including sickness absenteeism and mortality. We test two hypotheses. The first is Kanter's theory of tokenism, which suggests that minority group members suffer from an increased risk of stress. Secondly, we test the hypothesis that workplaces with a higher proportion of men will have a higher incidence rate of ischaemic heart disease (IHD), as men are more likely to engage in negative health behaviours, and through peer effects this will result in a workplace culture that is detrimental to health over the long term. Methods: Large-scale, longitudinal Swedish administrative register data are used to study the risk of overnight hospitalization for IHD amongst 67,763 men over the period 1990 to 2001. Discrete-time survival analyses were estimated in the form of logistic regression models. Results: Men have an elevated risk of suffering from IHD in non-gender-balanced workplaces, but this association was only statistically significant in workplaces with 61-80% and 81-100% males. However, after adjusting for occupation no clear pattern of association could be discerned. No pattern of association was observed for women. Conclusions: This study suggests that the gender composition of workplaces is not strongly associated with the risk of suffering from IHD.
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| 6. |
- Barclay, Kieron, 1986-
(författare)
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The Long-term Impact of Birth Order on Health and Educational Attainment
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis examines the long-term impact of birth order on health, and educational attainment. Swedish register data is used to link individuals to their siblings, thereby allowing members of the sibling group to be compared to one another. This thesis consists of an introductory chapter summarizing empirical research on the relationship between birth order and educational attainment, intelligence, health, and personality, as well the theoretical frameworks that have been developed to explain those relationships. This introductory chapter is followed by four original empirical studies. The first two studies show that relative to first born siblings, later borns have lower physical fitness in late adolescence, and higher mortality in adulthood. The third study uses the Swedish registers to identify sibling groups that entirely consist of adopted individuals, and shows that the commonly observed negative relationship between birth order and educational attainment persists in these fully adopted sibling groups. These results suggest that birth order effects are likely explained by post-natal, social mechanisms within the family. Finally, the fourth study shows that even though later born siblings do worse than first borns in a fully adjusted statistical model, educational expansion in the 20th century has meant that later born siblings actually tend to have greater educational attainment and are more likely to attend university in comparison to older siblings within the same family.
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