Grech, V

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LETTER TO THE EDITORThe effect of warfare on the secular trends in sexratios at birth in Israel, Egypt, and Kuwait overthe past 60 yearsIn mammals, gender is determined at conception andmale births occur slightly in excess (1). The male tofemale ratio of live births is technically incorrectlyreferred to as M/F as this is given as male divided by totalbirths, and it is expected to approximate 0.515 (1).A declining M/F has been observed in many indus-trialised countries since 1950 as the more fragile malefoetus may be spontaneously aborted at a higher ratethan the more robust female foetus when exposed tohypothetical deleterious environmental factor/s (2). Stresshas been shown to decrease M/F (3), while long-durationwarfare (such as the World Wars) increases it (4). Adverseenvironmental factors or traumatic experiences thataffect entire populations have both been shown to lowerM/F. For example, M/F declines after warfare (5), earth-quakes, and a multiplicity of environmental disasters (6).It appears that such events promote stressed preg-nant women to spontaneously abort male foetuses to agreater extent than female foetuses (7). M/F has thereforebeen proposed as a potential surrogate sentinel healthindicator (8).There is only one extant study which deals with M/F incountries located in the Middle East (9). This studiedIran and showed that M/F declined slowly between 1976and 1981, stabilised, and then rose up to 1999. M/Fdecreased significantly during periods of warfare whencompared with pre-war. There was also a decrease post-war when compared with pre-war.This study identifies secular trends in M/F in theMiddle East from a World Health Organization (WHO)dataset that includes the past 60 years. This dataset hasbeen utilised extensively in order to study M/F in SouthAmerica (10), Asia (11), and selected parts of Europe(12, 13).The only reliable datasets available were those ofIsrael, Egypt, and Kuwait. Chi square tests (includingtrend testing) were applied. The results are shown inFig. 1.There were 34,644,020 live births available for analysis.Israel displayed a significant decline in M/F from 1950 to1989 (x trend10.1, p0.0014). There was one outliervalue in 1981, when M/F dipped significantly. M/F thenappeared to have stabilised.Egypt also reported an overall (albeit less smooth)decline in M/F from 1955 to 2012 (x trend7664.108,pB0.0001). There was also a single outlier value in 1979,when M/F dipped significantly.Kuwait exhibited a significant decline in M/F from 1972to 1987 (x trend7.9, p0.005). M/F then increasedsharply and significantly from 198587 to 199395 (datamissing for 198892) and this increase is statisticallysignificant (x7.9, p0.0005). M/F then declined againduring 19932009 (x trend15.9, pB0.0001).M/F has been shown to be declining in Europe and inNorth America (14), and the results obtained in thisstudy are in accordance with this trend.In 1978, Egypt and Israel signed the Camp DavidAccords, which resulted in the signing of the IsraelEgypt Peace Treaty in the following year. One wonderswhether these events are somehow related to the EgyptianM/F dip in 1979.In 1981, Israeli forces destroyed a nuclear reactor thatwas still under construction near Baghdad. One wonderswhether the spectre of war provided sufficient stress tocause a dip in M/F in Israel.In conclusion, this study shows that M/F in this re-gion, for the countries available for study, is in decline,similar to the situation in Europe and North America(14).AcknowledgementsMie Inoue and Gauden Galea from the World Health Organization.Conflict of interest and fundingThe author has not received any funding or benefits fromindustry or elsewhere to conduct this study.Victor GrechDepartment of PaediatricsMater Dei HospitalL-Imsida, MaltaEmail: victor.e.grech@gov.mtLibyan Journal of MedicineLibyan Journal of Medicine 2014. # 2014 Victor Grech. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction inany medium, provided the original work is properly cited.1Citation: Libyan J Med 2014, 9: 23448 - http://dx.doi.org/10.3402/ljm.v9.23448(page number not for citation purpose)References1. James WH. The human sex ratio. Part 1: a review of theliterature. Hum Biol. 1987; 59: 72152.2. James WH. Evidence that mammalian sex ratios at birth arepartially controlled by parental hormone levels around the timeof conception. J Endocrinol. 2008; 198: 315.3. Catalano RA. Sex ratios in the two Germanies: a test of theeconomic stress hypothesis. Hum Reprod. 2003; 18: 19725.4. Houdaille J. Le rapport de masculinite. Population et Societes.1973; 61: 13.5. Zorn B, Sucur V, Stare J, Meden-Vrtovec H. Decline in sex ratioat birth after 10-day war in Slovenia: brief communication.Hum Reprod. 2002; 17: 31737.Fig. 1. M/F trends for Israel, Egypt, and Kuwait.Victor Grech2(page number not for citation purpose)Citation: Libyan J Med 2014, 9: 23448 - http://dx.doi.org/10.3402/ljm.v9.234486. Lyster WR. Altered sex ratio after the London smog of 1952and the Brisbane flood of 1965. J Obstet Gynaecol BrCommonw. 1974; 81: 62631.7. Byrne J, Warburton D. Male excess among anatomically normalfetuses in spontaneous abortions. Am J Med Genet. 1987; 26:60511.8. Davis DL, Gottlieb MB, Stampnitzky JR. Reduced ratio ofmale to female births in several industrial countries: a sentinelhealth indicator? JAMA. 1998; 279: 101823.9. Ansari-Lari M, Saadat M. Changing sex ratio in Iran, 19762000. J Epidemiol Community Health. 2002; 56: 6223.10. Grech V. Secular trends in sex ratios at birth in South Americaover the second half of the 20th century. J Pediatr (Rio J) 2013;89: 5059.11. Grech V. Secular trends and latitude gradients in sex ratios atbirth in Asia over the past sixty years. Pediatr Int. 2013; 55:21922.12. Grech V. Sex ratios at birth in the British Isles over the past sixtyyears. Eur J Pediatr. 2013; 172: 5258.13. Grech V. Declining male births in Germany before and afterreunification. Turk J Pediatr. 2013; 55: 3003.14. Grech V, Vassallo-Agius P, Savona-Ventura C. Secular trends insex ratios at birth in North America and Europe over the secondhalf of the 20th century. J Epidemiol Community Health. 2003;57: 61215.Letter to the editorCitation: Libyan J Med 2014, 9: 23448 - http://dx.doi.org/10.3402/ljm.v9.23448 3(page number not for citation purpose)

Letter to the Editor: The effect of warfare on the secular trends in sex ratios at birth in Israel, Egypt, and Kuwait over the past 60 years

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Letter to the Editor: The effect of warfare on the secular trends in sex ratios at birth in Israel, Egypt, and Kuwait over the past 60 years

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