Cerebrospinal fluid monoamine metabolite levels in human newborn infants born in winter differ from those born in summer

Is personality linked to season of birth?

The environment is a very significant factor in early childhood development. Season of birth (SOB) is a proxy viable for the environment to which the babies are exposed, thus also significant in early development. This study investigates the association between SOB and personality. A total 2,962 college students were included as study participants. The participants were classified into four seasonal groups based on their birth month and underwent a personality assessment using the Temperament and Character Inventory (TCI). Statistical analysis was performed using one-way analysis of variance (ANOVA) and multinomial logistic regression analysis. The male participants born in autumn scored high on the Disorderliness (NS4) subscale (β = 0.055, P = 0.042) and the male participants born in summer and winter scored high on the Extravagance (NS3) subscale (summer: β = 0.072, P = 0.01, winter: β = 0.078, P = 0.003). The difference observed indicates a relationship between the SOB and temperament, especially NS. Our findings suggest that environmental factors may affect temperament in early development, although further research is likely needed to clarify the causality between them.

Season of birth is different in Inuit suicide victims born into Traditional than into Modern Lifestyle: a register study from Greenland

BACKGROUND

There is growing evidence that living conditions at birth play a role in medical conditions later in life. Population-based studies from the Northern Hemisphere have shown that persons born in the spring or summer are at greater risk of committing suicide. A statistical correlation with light availability at birth has been observed in past research, but the cause remains unknown. Greenland is one of the most extreme of natural human habitats with regard to seasonal changes in light. The combination of rapid social changes and reliable population statistics offers a unique opportunity to make comparisons between persons born into a Traditional Lifestyle and those born into a Modern Lifestyle. The aim of this work was to assess whether season of birth differed between suicide victims born into an old or into a modern lifestyle.

METHODS

Official population and mortality registers were used. Suicide victims born (1903-1950) into the Traditional Lifestyle were compared with those born into the Modern Lifestyle (1961-1980). Rayleigh's test for circular distributions was used to assess the season of birth in suicide victims. Data regarding season of birth in the general population were collected.

RESULTS

Persons born in March-June in the Traditional Lifestyle were much less likely to commit suicide than those born during other periods of the year. This is contrary to the findings of other studies. The seasonal differences had disappeared for those born into the Modern Lifestyle. The suicide rate increased from very low rates to about 140 suicides/100 000 person-years in the 1980s.

CONCLUSIONS

The reason behind a variation in season of birth in suicide victims born into the old lifestyle is unknown. It is also unknown why the seasonal difference had disappeared with modern lifestyle. Possible influence of artificial light, nutrition, microbiota and seasonal infections are discussed. The underlying causes behind suicides may be different in traditional and modern Greenland.

Season of birth in suicides: excess of births during the summer among schizophrenic suicide victims

BACKGROUND

Season of birth is associated with several psychiatric disorders and suicidal behavior. We explored the association between the season of birth and suicide among schizophrenic and psychotic suicide victims.

METHODS

The study sample consisted of all suicides in the province of Oulu in Northern Finland from 1989 to 2010. Causes of death were extracted from death certificates, and psychiatric diagnoses associated with the hospital treatments were obtained from the Finnish Hospital Discharge Register. The seasons were defined as follows: winter (from November to January), spring (from February to April), summer (from May to July), and autumn (from August to October). Suicide victims (n = 1,902) were categorized as having either schizophrenia (n = 228) or psychosis other than schizophrenia (n = 240). Suicide victims without any hospital-treated mental disorder (n = 1,434) were used as a comparison group.

RESULTS

The distribution of births among suicide victims with schizophrenia differed statistically significantly from that observed in the general population, with a peak in summer (OR 1.2, 95% CI 1.0-1.5).

CONCLUSIONS

Birth during summer may predispose schizophrenic persons to suicide. The putative roles of serotonin, dopamine, and vitamin D status in the season of birth of psychotic suicide victims are discussed.

Seasonal variation of serotonin turnover in human cerebrospinal fluid, depressive symptoms and the role of the 5-HTTLPR

Studying monoaminergic seasonality is likely to improve our understanding of neurobiological mechanisms underlying season-associated physiological and pathophysiological behavior. Studies of monoaminergic seasonality and the influence of the serotonin-transporter-linked polymorphic region (5-HTTLPR) on serotonin seasonality have yielded conflicting results, possibly due to lack of power and absence of multi-year analyses. We aimed to assess the extent of seasonal monoamine turnover and examined the possible involvement of the 5-HTTLPR. To determine the influence of seasonality on monoamine turnover, 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were measured in the cerebrospinal fluid of 479 human subjects collected during a 3-year period. Cosine and non-parametric seasonal modeling were applied to both metabolites. We computed serotonin (5-HT) seasonality values and performed an association analysis with the s/l alleles of the 5-HTTLPR. Depressive symptomatology was assessed using the Beck Depression Inventory-II. Circannual variation in 5-HIAA fitted a spring-peak cosine model that was significantly associated with sampling month (P=0.0074). Season of sampling explained 5.4% (P=1.57 × 10(-7)) of the variance in 5-HIAA concentrations. The 5-HTTLPR s-allele was associated with increased 5-HIAA seasonality (standardized regression coefficient=0.12, P=0.020, N=393). 5-HIAA seasonality correlated with depressive symptoms (Spearman's rho=0.13, P=0.018, N=345). In conclusion, we highlight a dose-dependent association of the 5-HTTLPR with 5-HIAA seasonality and a positive correlation between 5-HIAA seasonality and depressive symptomatology. The presented data set the stage for follow-up in clinical populations with a role for seasonality, such as affective disorders.

Star-crossed? The association of the 5-HTTLPR s allele with season of birth in a healthy female population, and possible consequences for temperament, depression and suicide

BACKGROUND

Birth season has well-known effects on neuropsychiatric disorders, and may also influence genotype distribution by possibly influencing chance of conception via parental idiosyncratic conception patterns or survival of foetuses or infants. The 5-HTTLPR is associated with phenomena including affective temperaments or suicide which are also associated with birth season. Our aim was to investigate the association of 5-HTTLPR genotype and birth season in a healthy female population.

METHODS

Birth date and 5-HTTLPR genotype was determined for 327 psychiatrically healthy women. The association between presence of s allele and time of birth was analysed using generalized linear models.

RESULTS

A significant association between s allele frequency and time of birth was detected. S allele carrier frequency was marginally significantly higher in July borns and significantly lower in autumn borns.

LIMITATIONS

We investigated an adult sample so genotype frequency data do not reflect birth frequencies. Our sample consisted exclusively of females.

CONCLUSIONS

There is no clear explanation for the observed association, although idiosyncratic parental conception patterns, the association of 5-HTTLPR with sudden infant/intrauterine death, or other s allele-mediated behaviours may play a role. Our results are strikingly parallel with earlier data reporting a higher risk of completed suicide in July borns, and higher scores of July borns and lower scores of autumn borns on certain affective temperament scales, both of which are also associated with the s allele of 5-HTTLPR. Thus our results may add to the growing body of evidence regarding the etiological background of affective disorders.

Relationships of Un and Gi seasons of birth to clinical symptoms and signs

OBJECTIVES

Season of birth (SOB) is a medical term used to describe the relationship between the season in which one is born and his or her physiologic and pathological characteristics. In East Asian medicine, the Un-Gi SOB is based on the Yin-yang-Five Phases theory. The purpose of this study is to examine the relationship between Un-Gi SOB and a multitude of clinical symptoms and signs, and to examine which of the Un and Gi seasons has the greatest impact on these symptoms and signs.

METHODS

Using the Delphi method, three Un-Gi experts formulated a 26-item questionnaire consisting of clinical symptoms and signs, with each item rated on a Likert 7-point scale. A total of 1057 Korean adolescents (583 males, 474 females) completed the 26-item questionnaire. After identifying the Un and Gi seasons of all subjects, item scores were evaluated to determine whether there was a difference between Un and Gi seasons.

RESULTS

For Un seasons, males born in the Wood season had greater indigestion and were less physically active, whereas females born in the Earth season were better able to concentrate but had slower rates of growth. For Gi seasons, males born in the Fire season had greater indigestion and morning fatigue, and males born in the Earth season had higher tension. There was no relationship between symptoms, signs, and the Gi SOB in females. This indicates that males born in Wood Un and Gi seasons are susceptible to Earth-related clinical problems, whereas females born in the Earth Un season are susceptible to Earth-related clinical problems.

CONCLUSIONS

The study results suggest that Un-Gi seasons based on the Yin-yang-Five Phases are related to clinical symptoms and signs, with significant differences between genders.

Season of sampling and season of birth influence serotonin metabolite levels in human cerebrospinal fluid

Background

Animal studies have revealed seasonal patterns in cerebrospinal fluid (CSF) monoamine (MA) turnover. In humans, no study had systematically assessed seasonal patterns in CSF MA turnover in a large set of healthy adults.

Methodology/Principal Findings

Standardized amounts of CSF were prospectively collected from 223 healthy individuals undergoing spinal anesthesia for minor surgical procedures. The metabolites of serotonin (5-hydroxyindoleacetic acid, 5-HIAA), dopamine (homovanillic acid, HVA) and norepinephrine (3-methoxy-4-hydroxyphenylglycol, MPHG) were measured using high performance liquid chromatography (HPLC). Concentration measurements by sampling and birth dates were modeled using a non-linear quantile cosine function and locally weighted scatterplot smoothing (LOESS, span = 0.75). The cosine model showed a unimodal season of sampling 5-HIAA zenith in April and a nadir in October (p-value of the amplitude of the cosine = 0.00050), with predicted maximum (PC_max) and minimum (PC_min) concentrations of 173 and 108 nmol/L, respectively, implying a 60% increase from trough to peak. Season of birth showed a unimodal 5-HIAA zenith in May and a nadir in November (p = 0.00339; PC_max = 172 and PC_min = 126). The non-parametric LOESS showed a similar pattern to the cosine in both season of sampling and season of birth models, validating the cosine model. A final model including both sampling and birth months demonstrated that both sampling and birth seasons were independent predictors of 5-HIAA concentrations.

Conclusion

In subjects without mental illness, 5-HT turnover shows circannual variation by season of sampling as well as season of birth, with peaks in spring and troughs in fall.

Novel Mutations in the Tyrosine Hydroxylase Gene in the First Czech Patient with Tyrosine Hydroxylase Deficiency

Tyrosine hydroxylase deficiency manifests mainly in early childhood and includes two clinical phenotypes: an infantile progressive hypokinetic-rigid syndrome with dystonia (type A) and a neonatal complex encephalopathy (type B). The biochemical diagnostics is exclusively based on the quantitative determination of the neurotransmitters or their metabolites in cerebrospinal fluid (CSF). The implementation of neurotransmitter analysis in clinical praxis is necessary for early diagnosis and adequate treatment. Neurotransmitter metabolites in CSF were analyzed in 82 children (at the age 1 month to 17 years) with clinical suspicion for neurometabolic disorders using high performance liquid chromatography (HPLC) with electrochemical detection. The CSF level of homovanillic acid (HVA) was markedly decreased in three children (64, 79 and 94 nmol/l) in comparison to age related controls (lower limit 218–450 nmol/l). Neurological findings including severe psychomotor retardation, quadruspasticity and microcephaly accompanied with marked dystonia, excessive sweating in the first patient was compatible with the diagnosis of tyrosine hydroxylase (TH) deficiency (type B) and subsequent molecular analysis revealed two novel heterozygous mutations c.636A>C and c.1124G>C in theTHgene. The treatment with L-DOPA/carbidopa resulted in the improvement of dystonia. Magnetic resonance imaging studies in two other patients with microcephaly revealed postischaemic brain damage, therefore secondary HVA deficit was considered in these children. Diagnostic work-up in patients with neurometabolic disorders should include analysis of neurotransmitter metabolites in CSF.

Association between affective temperaments and season of birth in a general student population

BACKGROUND

Several studies indicate a significant association between birth season and personality and neuropsychiatric disorders. The aim of our present study was to investigate the association between affective temperaments and season of birth in a nonclinical sample.

METHODS

366 university students completed the standardized Hungarian version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Auto-questionnaire (TEMPS-A). Ordinary Least Squares regression was applied to explain the relationship between TEMPS-A subscale and birth season of the respondents.

RESULTS

We found a significant association between temperament scores and birth season in the case of the Hyperthymic, Cyclothymic, Irritable and Depressive temperaments, while no significant results emerged for the Anxious temperament.

LIMITATIONS

The relatively small sample size, especially in the case of seasonal and monthly subsamples limits generalization of our results.

CONCLUSIONS

Our results support the evidence that there is a strong association between season of birth and personality, extending the results to affective temperaments as well. Furthermore, our results are in line with clinical observations concerning the seasonal variation of onset and hospitalization due to affective episodes. This is especially important, since affective temperaments are conceived as the subaffective and subclinical manifestations of major and minor affective disorders indicating a risk for the development of these disorders and also exerting a possible pathoplastic effect, thus our results also have clinical significance.

Cognitive and emotional processing associated with the Season of Birth and dopamine D4 receptor gene

The 7-repeats variant of the dopamine D4 receptor (7R) VNTR polymorphism has been associated with higher novelty seeking (NS) and disadvantageous decision making in the Iowa Gambling Task (IGT). Season of Birth (SOB) is a significant determinant of NS. SOB and L-DRD4 genetic polymorphism may independently and interactively influence similar behaviors through their common effects on the dopaminergic system. Two hundred and twenty-seven healthy males grouped in summer-born/4-repeats (4R) (n=75), winter-born/4R (n=90), summer-born/7R (n=31) and winter-born/7R (n=31) groups, completed multimodal assessment for personality, planning for problem solving and decision making. Winter-born/7R subjects had significantly worse IGT performance throughout the task compared to 4R individuals, while summer-born 7R subjects had intermediate, although not significantly different performance. Moreover, winter-born/7R subjects had increased behavioral approach to reward without parallel reduction in sensitivity to fear or to social approval cues. The DRD4-by-SOB groups did not differ in planning for problem solving. These results suggest that a DRD4-by-SOB interaction is associated with increased behavioral approach to reward and risk taking but efficient problem solving. In addition, these results further support the hypothesis that SOB modifies the behavioral expression of dopaminergic genetic polymorphism. SOB should be included in future studies of risky behaviors and behavioral genetic studies of the dopamine system.

Season of birth is significantly associated with the risk of completed suicide

BACKGROUND

Previous studies have provided somewhat inconsistent results about the effects of season of birth on the risk of suicidal behavior. Therefore, we decided to investigate this question in a large sample of suicide completers.

METHODS

We determined the season of birth-associated risk of completed suicide between the years 1970 and 2008 among all individuals who were born in the area of today's Hungary between 1930 and 1939, 1941 and 1942, and 1944 and 1969.

RESULTS

The final sample of participants included around six and a half million people. About 80,000 completed suicides occurred among participants during the period investigated (the number of suicide completers in our study greatly exceeds the number of suicide completers in any previous studies). A significantly (p < .05) elevated risk of completed suicide was found among those individuals who were born in the high-risk period (spring and summer). Quantitatively, the biggest increase (7.6% [95% confidence interval: 5.4-9.9]) in suicide risk was detected among those who were born in July compared with the average risk of suicide in the population investigated. The associations between season of birth and the risk of completed suicide were stronger among male subjects than among female subjects and among those who committed suicide using violent methods than among those who chose nonviolent methods.

CONCLUSIONS

Our results from a large sample of suicide completers from Hungary--a country with one of the highest suicide rates in the world over the last century--strongly support the concept that the season of birth is significantly associated with the risk of completed suicide.

An association between month of birth and method of suicide

Abstract Background. A statistically significant association between season of birth and suicidal behaviour has been reported. However, the effect of month of birth on the choice of suicide method is yet to be established. Aim. This study examines the association between commonly used methods of suicide and season of birth using data on suicide collected over a 21-year period in England, Wales and Scotland. The sample size available, in excess of 52,000 suicides, greatly exceeds all previous studies in this field. Method. Data on suicides registered between 1979 and 2000® were obtained from the Office for National Statistics (ONS) for England and Wales, and the General Register Office (GRO) for Scotland. Our analyses include all suicides [ICD 9 codes; E950- E959] and undetermined injury deaths [E980-E989], reported between 1979 and 2000 in England, Wales and Scotland for persons born between 1941 and 1966. We used Poisson and negative binomial generalised linear models (GLMs) with seasonal harmonic components. Results. Adjusting for the year of birth, the model predicts that the average increase in risk of suicide between the trough (October) and the peak (May) of the seasonal component is 17.9% (95% CI= 13-33%). For males the estimated increase in risk was 15% (95% CI 5-22%) and for females 27% (95% CI 8-47%). The effect of month of birth on suicide applied to all commonly used methods, with the exception of suicide by burning (SBB) with a significant increase of 16% (95% CI 2-37%) in people born in January compared to other methods. Conclusion. Our results replicate our earlier finding of an association between season of birth and suicide incidence. Birth rates of persons who kill themselves show a disproportionate excess in spring compared to other months. The unexpected observed finding in suicide by burning (SBB) may represent the effect of latitude and warrants further examination. Seasonality of birth in suicide may enhance our understanding of some biological aspects in its aetiology and give directions for future research.

Novelty seeking among adult women is lower for the winter borns compared to the summer borns: replication in a large Finnish birth cohort

OBJECTIVE

Earlier general population studies have shown that novelty seeking (NS) of the Temperament and Character Inventory (TCI) of personality is lower for persons born in winter compared to those born in summer, particularly for women. Here, we investigate if this result can be replicated in another population.

METHOD

The Northern Finland 1966 Birth Cohort, comprising 4968 subjects (2725 women, 2243 men), was investigated with regard to the temperament dimensions of the TCI and the season of birth.

RESULTS

Novelty seeking and reward dependence (RD) showed significant variations according to the month of birth. We found that women born during winter have significantly lower levels of NS compared to women born during summer, with a minimum for the birth month November and maximum for May. These results are similar to those found in a previous Swedish study. Furthermore, our study showed that men born during spring had significantly lower mean scores of RD compared to men born during autumn, with a minimum for birth month March. This was in contrast to the Swedish study, where the minimum of RD was obtained for the birth month December.

CONCLUSION

Women born in winter have lower NS as adults compared to women born in summer. Because NS is modulated by dopamine, this study gives further support to the studies in the literature that show that dopamine turnover for those born in winter is higher than for those born in summer.

Clinical Utility of Monoamine Neurotransmitter Metabolite Analysis in Cerebrospinal Fluid

Background: Measurements of monoamine neurotransmitters and their metabolites in plasma and urine are commonly used to aid in the detection and monitoring of neuroblastoma and pheochromocytoma and the evaluation of hypotension or hypertension. Measurements of these neurotransmitters and metabolites can also be helpful in the investigation of disorders that primarily affect the central nervous system, but only when the measurements are made in cerebrospinal fluid (CSF).

Content: I describe CSF profiles of monoamine metabolites in the primary and secondary defects affecting serotonin and catecholamine metabolism. I outline the methods required to analyze these metabolites together with details of specific sample handling requirements, sample stability, and interfering compounds, and I emphasize a need for age-related reference intervals.

Summary: Measured values of monoamine metabolites in CSF provide only a single-time snapshot of the overall turnover of the monoamine neurotransmitters within the brain. Because these measurements reflect the average concentrations accumulated from all brain regions plus the regional changes that occur within the spinal cord, they may miss subtle abnormalities in particular brain regions or changes that occur on a minute-to-minute or diurnal basis. Clearly defined diagnosed disorders are currently limited to those affecting synthetic and catabolic pathways. In many cases, abnormal monoamine metabolite concentrations are found in CSF and an underlying etiology cannot be found. Molecular screening of candidate genes related to steps in the neurotransmission process, including storage in presynaptic nerve vesicles, release, interaction with receptors, and reuptake, might be a fruitful endeavor in these cases.