Season of Birth and Substance Abuse: Findings From a Large National Sample

Month of birth and mental disorders: A population-based study and validation using global meta-analysis

OBJECTIVE

Month of birth (MOB) is associated with specified mental disorders (MDs). However, whether these relationships extend to all MDs remains unclear. We investigate the association using a population-based cohort study and a meta-analysis.

METHODS

First, we examined patients with 34 DSM-5-classified MDs in the Taiwan national database. We estimated the relative risk ratios (RR) of each illness in each MOB relative to that in the general population and assessed the periodicity, with six further sensitivity analyses. Second, we searched PubMed, Embase, and Cochrane for related articles through 31 December 2020. We used a random-effects model, pooled RRs with 95% confidence intervals of each MOB from the identified studies, and transformed them from MOB to relative age in a year or season.

RESULTS

The cohort included 1,951,777 patients. Except for posttraumatic stress disorder, dissociative disorders, feeding/eating disorders, gender dysphoria, and paraphilic disorders, the other MDs had significant MOB periodicity. The meta-analysis included 51 studies investigating 10 MDs. The youngest age at the start of school owing to MOB was associated with the highest RRs of intellectual disability (1.13), autism (1.05), attention-deficit/hyperactivity disorder (1.13). Winter births had significant risks of schizophrenia (1.04), bipolar I disorder (1.02), and major depressive disorder (1.01), and autumn births had a significant risk of alcohol use disorder (1.02). No significant associations between season of birth and Alzheimer's disease, or eating disorders were found.

CONCLUSIONS

MOB is related to the risks of certain MDs. This finding provides a reference for future research on the etiology of MDs.

Birth month and mortality in Japan: a population-based prospective cohort study

Epidemiologic studies investigating the association between birth season and risk of mortality in adulthood are limited and have yielded inconclusive results. We aimed to examine the relationship between birth month and all-cause and cause-specific mortality, after controlling for potential confounders, including lifestyle and medical factors, in a population-based cohort study in Japan. We included 28,884 subjects (13,262 men and 15,622 women) from Takayama City, aged 35 years or older without cancer, stroke, and ischemic heart disease, who were born in Japan at baseline. Participants who were enrolled in 1992 were followed up for over 16 years. Information including place of birth, lifestyles, and medical history was obtained from a baseline questionnaire. We performed a Cox proportional hazards analysis to determine the association between birth month and all-cause and cause-specific mortality after adjusting for potential confounders. During the follow-up period (mean follow-up: 14.1 years), 5,303 deaths (2,881 men and 2,422 women) were identified. After controlling for multiple covariates, it was found that being born in April or June was associated with an increased risk of all-cause mortality compared to being born in January (hazard ratio [HR] 1.138; 95% confidence interval [CI], 1.006-1.288 and HR 1.169; 95% CI, 1.028-1.329, respectively). The HRs for cardiovascular mortality were significantly higher in participants born in March and May (HR 1.285; 95% CI, 1.056-1.565 and HR 1.293; 95% CI, 1.040-1.608, respectively). Our findings indicate that an individual's birth month may be an indicator of the susceptibility to mortality in later life.

Season of birth: A predictor of ADHD symptoms in early midlife

OBJECTIVE

In this longitudinal study, we applied linear regression analyses to examine season of birth as related to symptoms of attention deficit/hyperactivity disorder (ADHD) in early midlife.

METHOD

We gathered longitudinal data on a prospective cohort of community-dwelling men and women (N = 548) followed from adolescence to early midlife.

FINDINGS

The findings indicate that, as compared with participants who were born in the summer, those who were born in the spring (Beta = 0.34; t-statistic = 3.59; p < 0.001) had significantly more ADHD symptoms. In addition, exposure to maternal cigarette smoking in adolescence significantly intensified (p < 0.01) the association between season of birth and ADHD symptoms in early midlife.

CONCLUSION

These findings suggest that exposure to greater maternal maladaptive behaviors, such as cigarette smoking, may result in a greater vulnerability to other environmental risk factors, such as season of birth.

Neurodevelopmental and environmental hypotheses of negative symptoms of schizophrenia

The negative symptoms of schizophrenia, avolition, alogia, apathy and impaired or nonexistent social functioning, are strongly correlated with the progressive course and long-term prognosis of the disease, undermining the patient's ability to integrate socially, interpersonal skills and quality of life. At a time when new drug strategies are being developed, a better understanding of the etiology and pathogenesis underpinning the occurrence of negative symptoms constitutes an essential prerequisite for real therapeutic advances. Approaching this vulnerability from the neurodevelopmental perspective is especially pertinent with regard to the experimental studies conducted in animals. Several models have been put forward, involving a variety of topics such as the deleterious impact of a prenatal infection or of early maternal deprivation on brain development, or else the consequences of trauma and abuse suffered during childhood. These various models are based on biological abnormalities that could guide the identification of new therapeutic targets. They notably include the hyperreactivity of the hypothalamic-pituitary-adrenal axis and dysfunction of corticostriatal glutamatergic transmission. As such, in the traumagenic model, which associates neurodevelopmental and neurodegenerative processes, the dysfunction of corticostriatal glutamatergic transmission, by reducing the tonic dopamine release, could be the cause of an increase in the phasic dopamine release linked to stress. This excessive phasic response to stress may induce cerebral damage by increasing excitotoxicity and oxidative stress.

Month of birth and cause-specific mortality between 50 and 80 years: a population-based longitudinal cohort study in Sweden

Month of birth-a proxy for a variety of prenatal and early postnatal exposures including nutritional status, ambient temperature and infections-has been linked to mortality risk in adult life. We assessed the relation between month of birth and cause-specific mortality risk from cardiovascular diseases, infections, tumors and external causes-in ages of more than 50-80 years. In this nation-wide Swedish study, 4,240,338 subjects were followed from 1991 to 2010, using data from population-based health and administrative registries. The relation between month of birth and cause-specific mortality risk was assessed by fitting Cox proportional hazard regression models with attained age as the underlying time scale. In models adjusted for sex and education, month of birth was associated with cardiovascular and infectious mortality, but not with deaths from tumors or external causes. Compared with subjects born in November, a higher cardiovascular mortality was seen in subjects born from January through August, peaking in March/April [hazard ratio (HR) 1.066 compared to November, 95 % CI 1.045-1.086]. The mortality from infections was lowest for the birth months November and December and a distinct peak was observed for September-born (HR 1.108 compared to November, 95 % CI 1.046-1.175). Month of birth is associated with mortality from cardiovascular diseases and infections in ages of more than 50-80 years in Sweden. The mechanisms behind these associations remain to be elucidated.

Prenatal exposure to the 1944-45 Dutch 'hunger winter' and addiction later in life

AIMS

Prenatal exposure to severe famine has been associated with an increased risk of schizophrenia and affective disorders. We studied the relationship between prenatal exposure to famine during the Dutch hunger winter of 1944-45 and addiction later in life.

DESIGN

A case-control study.

SETTING

The Rotterdam city area during the Dutch hunger winter lasting from mid-October 1944 to mid-May 1945. From February 1945 to mid-May 1945 the hunger winter was characterized by a famine peak.

PARTICIPANTS

Patients are native Dutch addicted patients from the Rotterdam Addiction Treatment Program and controls are native Dutch inhabitants of Rotterdam, born between 1944 and 1947.

MEASUREMENT

Exposure to the whole hunger winter (< 1400 kcal/day) and the peak of the hunger winter (< 1000 kcal/day) was determined for each trimester of gestation. For each trimester the exposed/unexposed ratios were compared between patients and controls and quantified as odds ratios (OR).

FINDINGS

The odds of first-trimester gestational exposure to famine during the total hunger winter was significantly higher among patients receiving treatment for an addictive disorder [OR = 1.34, 95% confidence interval (CI) 1.10-1.64]. Stratification by sex shows that the odds of exposure during the first trimester was significantly higher only among men (OR = 1.34, 95% CI 1.05-1.72), but not among women (OR = 1.26, 95% CI 0.88-1.81). The odds of exposure to the peak of the hunger winter during the first trimester of gestation were also significantly higher among addiction treatment patients (OR = 1.61, 95% CI 1.22-2.12). We did not find any significant differences for the second and third trimesters of gestation.

CONCLUSION

First-trimester prenatal exposure to famine appears to be associated with addiction later in life. The study confirms the adverse influence of severe malnutrition on brain development and maturation, confirms the influence of perinatal insults on mental health in later life and gives rise to great concern about the possible future consequences for the hunger regions in our world.

Maternal exposure to first-trimester sunshine is associated with increased birth weight in human infants

Two alternative hypotheses have been generated to account for seasonal variation in the birth weight of human infants born in industrialized countries. First, it has been hypothesized that low ambient temperature during the second trimester of gestation decreases birth weight. Second, it has been hypothesized that exposure to bright sunshine during the first trimester increases birth weight. We tested these two hypotheses to determine which, if either, accounted for seasonal variation in birth weight of full-term infants. Birth weight data, collected over a 5-year period, were analyzed as a function of peak and trough sunshine and ambient temperature. Although there was no effect of ambient temperature during any trimester on birth weight, infants whose mothers were exposed to peak sunshine during their first trimester were born significantly heavier than infants whose mothers experienced trough levels of sunshine during the same trimester. Furthermore, infants whose mothers were exposed to trough levels of sunshine during their second and third trimesters were born significantly heavier than infants whose mothers were exposed to peak levels of sunshine during the same trimesters. We hypothesize that high levels of sunshine during early gestation may increase the level of insulin-like growth factor (IGF)-1, facilitating prenatal growth.

Season of birth effect on personality in a general population

Seasonality of births in schizophrenia and other mental disorders has been consistently observed. This may be through effects of unknown environmental factors that seasonally fluctuate on the brain development. The effects may affect cognitive function of the brain and behavioral characteristics that might be correlated with the development of personality not only in patients with mental disorders but also in healthy subjects. We, therefore, investigated the effects of season of birth on personality traits in healthy Japanese adults (n = 397). Personality traits were evaluated using the NEO Personality Inventory-Revised (NEO PI-R). A trend for lower Agreeableness in subjects born during winter (December to February) than other subjects was observed (P = 0.036, after correction for the multiple testing, multiple regression analysis adjusting for age and sex). Other major factors of the NEO PI-R, including Neuroticism, Extraversion, Openness and Conscientiousness, were not affected by season of birth. Further studies may be recommended to confirm the results, considering the relatively limited sample size. Evaluation of cognitive functions and behaviors using other measures including event-related potentials and functional MRI may also help the interpretation of the present result.

The "Christmas Effect" and other biometeorologic influences on childbearing and the health of women

OBJECTIVE

To review the body of literature addressing biometeorologic and chronobiologic effects on conception, pregnancy, parturition, and other health conditions.

DATA SOURCES

Computerized searches of MEDLINE, PUBMED, CINAHL, and the World Wide Web.

STUDY SELECTION

Studies, including international research, dating from 1938 to 2001.

DATA EXTRACTION

Data were extracted and information organized under the following categories: influence of leisure time and seasonality on the rate of conception and birth, the relationship of meteorologic changes and lunar cycles to childbearing, the "Christmas Effect" and its impact on other health outcomes, and nursing implications.

DATA SYNTHESIS

Research from the disciplines of biometeorology and chronobiology indicates that there are patterns in the occurrence of conception, pregnancy, and onset of labor that vary in timing and amplitude in different populations and geographic regions. Consideration of these factors should be included in the analysis of birth data when planning and providing maternity care. The Christmas Effect is one of the most predominant seasonal patterns that can be seen in birth data throughout the world.

CONCLUSIONS

Biometeorologic and other cyclic phenomena are underused in the United States in planning and providing maternity care. These phenomena warrant consideration when planning holistic health care.