Season of birth in schizophrenia in a
lower latitude country of northern hemisphere:
Bangladesh perspective
A.H. Mazumder(1)*, T. Islam(1), M.A. Rushdy(2), T.L. Hall(3), J. Iwatani(4)
Introduction
Methods
Re-emergence of influenza outbreaks in the context of some
vaccination failure, not only demands invention of effective flu shots
but also draw the attention of schizophrenia researchers and
epidemiologists. Influenza outbreak is common in winter and
pregnant women exposed to influenza during second trimester
increases the risk of adult onset schizophrenia among their
children. The birth rate of patients with schizophrenia has been
found to be 5–8 percent higher in the Winter-Spring period than in
the Summer-Autumn period, compared to the general
population [1] [2]. This finding is more consistent in northern than
southern hemisphere and in higher than lower latitude [3]. In some
other studies, summer birth has been found to be associated with
deficit schizophrenia [4]. Geographical location of Bangladesh in the
Tropic of Cancer in north hemisphere makes it a crucial place to
replicate similar researches.
This was a cross sectional, descriptive and analytical study done in a
tertiary level hospital of Bangladesh. Study sample size was 78. The
SCID-I and pre-designed questionnaire to explore socio demographic
data was applied. Positive and negative symptoms were assessed by
using the Positive and Negative Symptom Scale (PANSS). Statistical
analysis was done through SPSS version 17.
Results
According to the present study majority (59%) of the study subjects
were born in the winter. 29.50% of the study subjects were born in
the summer and 11.50% of the study subjects were born in the rainy
season. Our study result also revealed that summer and winter
births were likely to be more related with positive syndrome and
birth in the rainy season were more related with negative syndrome.
But the data were not statistically significant.
Association of season of birth with positive and
negative syndrome groups (n=78)
Season
of birth
Summer
Rainy
Winter
Total
Positive
Negative
Total
P-value
syndrome syndrome
23
15
8
65.2%
34.8% 100.0%
9 P=0.254
3
6
33.3%
66.7% 100.0%
46
27
19
58.7%
41.3% 100.0%
78
45
33
57.7%
42.3% 100.0%
Conclusions
The present study demonstrated significant association between
schizophrenia and winter birth and some association between
negative syndrome and birth in the rainy season, with some
limitations as being a single centered cross sectional study with
small sample size. More precise exploration of heterogeneity of
schizophrenia is needed for the development of research domain
criteria for schizophrenia.
(1)National Institute of Mental Health, Dhaka, Bangladesh
(2)Thikana Psychiatric and Drug Addiction Clinic, Dhaka, Bangladesh
(3)Hunter New England Mental Health Service, Newcastle, Australia
(4)Mental Health Clinic Si Può Fare, Sugano, Ichikawa, Chiba, Japan
Discussion
In Bangladesh, a study was conducted to assess the effect of season
of birth on schizophrenia in 1995 which showed that among the
schizophrenic patients 55.12% were born in winter followed by
20.51% and 17.94% in summer and spring respectively [5]. This result
was very much consistent with our result. In a review study from
population-based published studies from 6 countries including the
United States, Ireland, England, Scotland, Spain and France it was
found that, there was a significant difference between deficit and
non-deficit people in season of birth and that this difference was
largely due to an increase in deficit schizophrenia births in June and
July. From this, they concluded that deficit schizophrenia has a
season of birth pattern that differs from that of non-deficit
schizophrenia. And the authors suggested that deficit schizophrenia
might be a separate disease within the syndrome of
schizophrenia [4]. His result was similar to our results.
References
[1] Jordaan, E., Niehaus, D.J., Koen, L., et al., 2006. SAGE. Season of birth, age and negative symptoms in a Xhosa schizophrenia sample
from the Southern Hemisphere. Aust N Z J Psychiatry 40(8), 698–703.
[2] Jaana, M.S., Jari, K.H., Jouko K.L., 2001. American Psychiatric Association. Season of birth among patients with schizophrenia and
their siblings: evidence for the procreational habits hypothesis. Am J Psychiatry 158, 754–756.
[3] Messias, E., Mourao, C., Maia, J., et al., 2006. Lippincott Williams & Wilkins. Season of birth and schizophrenia in northeast Brazil
relationship to rainfall. J Nerv Ment Disease 194(11), 870–873.
[4] Messias, E., Kirkpatrick, B., Bromet, E., et al., 2004. American Medical Association. Summer birth and deficit schizophrenia a pooled
analysis from 6 countries. Arch Gen Psychiatry 61, 985–989.
t also revealed that summer and winter births were likely to be more related with positive syndrome and birth in the rainy season were
more related with negative syndrome. But the data were not statistically significant.
P.3.f.026
* Corresponding author: Dr. Atiqul Haq Mazumder ([email protected]): +8801713423349