| 1. |
- Catalano, Ralph A., et al.
(author)
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Collective Optimism and Selection Against Male Twins in Utero
- 2020
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In: Twin Research and Human Genetics. - : Cambridge University Press (CUP). - 1832-4274 .- 1839-2628. ; 23:1, s. 45-50
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Journal article (peer-reviewed)abstract
- Scholarly literature claims that health declines in populations when optimism about investing in the future wanes. This claim leads us to describe collective optimism as a predictor of selection in utero. Based on the literature, we argue that the incidence of suicide gauges collective optimism in a population and therefore willingness to invest in the future. Using monthly data from Sweden for the years 1973-2016, we test the hypothesis that the incidence of suicide among women of child-bearing age correlates inversely with male twin births, an indicator of biological investment in high-risk gestations. We find that, as predicted by our theory, the incidence of suicide at month t varies inversely with the ratio of twin to singleton male births at month t + 3. Our results illustrate the likely sensitivity of selection in utero to change in the social environment and so the potential for viewing collective optimism as a component of public health infrastructure.
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| 2. |
- Catalano, Ralph, et al.
(author)
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A novel indicator of selection in utero
- 2023
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In: EVOLUTION MEDICINE AND PUBLIC HEALTH. - : Oxford University Press (OUP). - 2050-6201. ; 11:1, s. 244-250
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Journal article (peer-reviewed)abstract
- Background and objectives: Selection in utero predicts that population stressors raise the standard for how quickly fetuses must grow to avoid spontaneous abortion. Tests of this prediction must use indirect indicators of fetal loss in birth cohorts because vital statistics systems typically register fetal deaths at the 20th week of gestation or later, well after most have occurred. We argue that tests of selection in utero would make greater progress if researchers adopted an indicator of selection against slow-growing fetuses that followed from theory, allowed sex-specific tests and used readily available data. We propose such an indicator and assess its validity as a dependent variable by comparing its values among monthly birth cohorts before, and during, the first 10 months of the COVID-19 pandemic in Sweden.Methodology: We apply Box-Jenkins methods to 50 pre-pandemic birth cohorts (i.e., December 2016 through January 2020) and use the resulting transfer functions to predict counterfactual values in our suggested indicator for selection for ten subsequent birth cohorts beginning in February 2020. We then plot all 60 residual values as well as their 95% detection interval. If birth cohorts in gestation at the onset of the pandemic lost more slow-growing fetuses than expected from history, more than one of the last 10 (i.e. pandemic-exposed) residuals would fall below the detection interval.Results: Four of the last 10 residuals of our indicator for males and for females fell below the 95% detection interval.Conclusions and implications: Consistent with selection in utero, Swedish birth cohorts in gestation at the outset of the COVID-19 pandemic included fewer than expected infants who grew slowly in utero. Lay Summary Our findings suggest that the risk of spontaneously aborting a slow-growing fetus will increase during relatively stressful times.
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| 3. |
- Andersen, Lars H., et al.
(author)
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Risk of stress/depression and functional impairment in Denmark immediately following a COVID-19 shutdown
- 2021
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In: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 21:1
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Journal article (peer-reviewed)abstract
- Background: Existing estimates of the impact of the COVID-19 burden on mental wellbeing come from countries with high mortality rates. This study therefore aimed to investigate the impact of the first COVID-19 lockdown (March–April 2020) on risk for stress/depression and functional impairment in a representative sample of adult individuals in Denmark, which had lower infection rates, and whether the impact of lockdown was heterogeneous across living situation.Methods: Using a representative, randomly drawn sample from the complete Danish adult population interviewed in March 2 to April 13, 2020 (n= 2836) and again in July 2020 (n= 1526, 54% retention rate), we study how the imposed lockdown announced March 11 following the onset of the first Danish wave of COVID-19 infections affected mental wellbeing. We use the World Health Organization Five Well-being Index (WHO-5) and the Work and Social Adjustment Scale (WSAS) to capture risk for stress/depression (WHO-5 < 50) and functional impairment (WSAS> 10). Using covariate adjusted ordinary least squares linear probability models and exploiting variation in the timing of responses occurring just before and just after the introduction of lockdown, we compare respondents before lockdown to respondents that answered during lockdown, as well as to answers in re-interviews in July.Results: In our fully controlled models, we find reduced depressive symptoms among adults immediately after the shutdown, concentrated in adults with children living at home (−.089, p< .01 (from pre lockdown baseline .273)). Measures of functional impairment also declined immediately after the March shutdown among adults with children living at home (−.066, p< .05 (from pre lockdown baseline .150)). Impairment intensified for the entire sample between March and July (+.199, p< .001 (from pre lockdown baseline .248)), but depressive symptoms remained at lower rate in July (−.033, p< .05 (from pre lockdown baseline .332).Conclusions: Findings in Denmark indicate that living with children at home may have, in the short term, buffered the potential mental health sequelae of the COVID-19 shutdown.
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| 4. |
- Bruckner, Tim .A., et al.
(author)
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Cold ambient temperature in utero and birth outcomes in Uppsala, Sweden, 1915 to 1929
- 2014
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In: Annals of Epidemiology. - : Elsevier BV. - 1047-2797 .- 1873-2585. ; 24:2, s. 116-121
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Journal article (peer-reviewed)abstract
- PurposeAlthough the literature reports adverse birth outcomes following ambient heat, less work focuses on cold. We, moreover, know of no studies of cold that examine stillbirth. We tested the relation between cold ambient temperature during pregnancy in Sweden and four outcomes: stillbirth, preterm, birth weight for gestational age, and birth length. We examined births from 1915 to 1929 in Uppsala, Sweden, which—unlike most societies today—experienced substandard indoor-heating and fewer amenities to provide shelter from cold.MethodsWe retrieved data on almost 14,000 deliveries from the Uppsala Birth Cohort Study. We linked a validated, daily ambient temperature series to all pregnancies and applied Cox proportional hazards (stillbirth and preterm) and linear regression models (birth weight and length). We tested for nonlinearity using quadratic splines.ResultsThe risk of stillbirth rose as ambient temperature during pregnancy fell (hazard ratio for a 1°C decrease in temperature, 1.08; 95% confidence interval, 1.00 to 1.17). Cold extremes adversely affected preterm and birth length, whereas warm extremes increased preterm risk. We observed no relation between cold and birth weight for gestational age.ConclusionIn historical Sweden, cold temperatures during pregnancy increased stillbirth and preterm risk and reduced birth length among live births.
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| 5. |
- Bruckner, Tim A., et al.
(author)
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Culled males, infant mortality and reproductive success in a pre-industrial Finnish population
- 2015
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In: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282:1799
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Journal article (peer-reviewed)abstract
- Theoretical and empirical literature asserts that the sex ratio (i.e. M/F) at birth gauges the strength of selection in utero and cohort quality of males that survive to birth. We report the first individual-level test in humans, using detailed life-history data, of the 'culled cohort' hypothesis that males born to low annual sex ratio cohorts show lower than expected infant mortality and greater than expected lifetime reproductive success. We applied time-series and structural equation methods to a unique multi-generational dataset of a natural fertility population in nineteenth century Finland. We find that, consistent with culled cohorts, a 1 s.d. decline in the annual cohort sex ratio precedes an 8% decrease in the risk of male infant mortality. Males born to lower cohort sex ratios also successfully raised 4% more offspring to reproductive age than did males born to higher cohort sex ratios. The offspring result, however, falls just outside conventional levels of statistical significance. In historical Finland, the cohort sex ratio gauges selection against males in utero and predicts male infant mortality. The reproductive success findings, however, provide weak support for an evolutionarily adaptive explanation of male culling in utero.
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| 6. |
- Cardona, Marcelo, et al.
(author)
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Stress/depression across the COVID-19 pandemic in Denmark
- 2023
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In: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 23:1
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Journal article (peer-reviewed)abstract
- Background Global estimates suggest strained mental health during the first year of the COVID-19 pandemic, but the lack of nationally representative and longitudinal data with clinically validated measures limits knowledge longer into the pandemic.Methods Data from 10 rounds of nationally representative surveys from Denmark tracked trends in risk of stress/depression from just before the first lockdown and through to April 2022. We focused on age groups and men and women in different living arrangements and controlled for seasonality in mental health that could otherwise be spuriously related to pandemic intensity.Results Prior to first lockdown, we observed a “parent gap”, which closed with the first lockdown. Instead, a gender gap materialized, with women experiencing higher risks than men—and higher than levels predating first lockdown. Older respondents (+ 70 years) experienced increasing risks of stress/depression early in the pandemic, while all other groups experienced decreases. But longer into the pandemic, risks increased for all age groups and reached (and sometimes exceeded) levels from before first lockdown.Conclusion Denmark had low infection rates throughout most of the pandemic, low mortality rates across the entire pandemic, and offered financial aid packages to curb financial strains. Despite this circumstance, initial improvements to mental health during the first lockdown in Denmark were short-lived. Two years of pandemic societal restrictions correspond with deteriorating mental health, as well as a change from a parenthood gap in mental health before first lockdown to a gender gap two years into the pandemic.
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| 7. |
- Catalano, Ralph, et al.
(author)
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Sildenafil and suicide in Sweden
- 2021
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In: European Journal of Epidemiology. - : Springer Nature. - 0393-2990 .- 1573-7284. ; 36:5, s. 531-537
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Journal article (peer-reviewed)abstract
- Much theory asserts that sexual intimacy sustains mental health. Experimental tests of such theory remain rare and have not provided compelling evidence because ethical, practical, and cultural constraints bias samples and results. An epidemiologic approach would, therefore, seem indicated given the rigor the discipline brings to quasi-experimental research. For reasons that remain unclear, however, epidemiologist have largely ignored such theory despite the plausibility of the processes implicated, which engender, for example, happiness, feelings of belonging and self-worth, and protection against depression. We use an intent-to-treat design, implemented via interrupted time-series methods, to test the hypothesis that the monthly incidence of suicide, a societally important distal measure of mental health in a population, decreased among Swedish men aged 50-59 after July 2013 when patent rights to sildenafil (i.e., Viagra) ceased, prices fell, and its use increased dramatically. The test uses 102 pre, and 18 post, price-drop months. 65 fewer suicides than expected occurred among men aged 50-59 over test months following the lowering of sildenafil prices. Our findings could not arise from shared trends or seasonality, biased samples, or reverse causation. Our results would appear by chance fewer than once in 10,000 experiments. Our findings align with theory indicating that sexual intimacy reinforces mental health. Using suicide as our distal measure of mental health further implies that public health programming intended to address the drivers of self-destructive behavior should reduce barriers to intimacy in the middle-aged populations.
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| 8. |
- Catalano, Ralph, et al.
(author)
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Twinning during the pandemic : Evidence of selection in utero
- 2021
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In: Evolution, Medicine, and Public Health. - : Oxford University Press. - 2050-6201. ; 9:1, s. 374-382
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Journal article (peer-reviewed)abstract
- Background and objectives: The suspicion that a population stressor as profound as the COVID-19 pandemic would increase preterm birth among cohorts in gestation at its outset has not been supported by data collected in 2020. An evolutionary perspective on this circumstance suggests that natural selection in utero, induced by the onset of the pandemic, caused pregnancies that would otherwise have produced a preterm birth to end early in gestation as spontaneous abortions. We test this possibility using the odds of a live-born twin among male births in Norway as an indicator of the depth of selection in birth cohorts.Methodology: We apply Box-Jenkins methods to 50 pre-pandemic months to estimate counterfactuals for the nine birth cohorts in gestation in March 2020 when the first deaths attributable to SARS-CoV-2 infection occurred in Norway. We use Alwan and Roberts outlier detection methods to discover any sequence of outlying values in the odds of a live-born twin among male births in exposed birth cohorts.Results: We find a downward level shift of 27% in the monthly odds of a twin among male births beginning in May and persisting through the remainder of 2020.Conclusions and implications: Consistent with evolutionary theory and selection in utero, birth cohorts exposed in utero to the onset of the COVID-19 pandemic yielded fewer male twins than expected.Lay Summary: Our finding of fewer than expected male twin births during the onset of the COVID-19 pandemic provides more evidence that evolution continues to affect the characteristics and health of contemporary populations.
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