{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,2,2]],"date-time":"2025-02-02T18:40:31Z","timestamp":1738521631672,"version":"3.35.0"},"reference-count":80,"publisher":"BMJ","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Epidemiology & Community Health"],"published-print":{"date-parts":[[1970,5,1]]},"DOI":"10.1136\/jech.24.2.78","type":"journal-article","created":{"date-parts":[[2008,11,12]],"date-time":"2008-11-12T19:49:51Z","timestamp":1226519391000},"page":"78-88","source":"Crossref","is-referenced-by-count":0,"title":["Anencephalus in Belfast. Incidence and secular and seasonal variations, 1950-66."],"prefix":"10.1136","volume":"24","author":[{"given":"J H","family":"Elwood","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","reference":[{"key":"ref_1","article-title":"Present series Present series Cahalane, Kennedy, McNicholl, and","author":"Stevenson; Warnock","year":"1959","unstructured":"Stevenson and Warnock (1959) Present series Present series Cahalane, Kennedy, McNicholl, and SpeOl'lDmwayne(r19(6199)65) Laurence et al (1968a) Record and McKeown (1949) Walker and Smith (1961) Pleydell (1960) McDonald (1961) Ward and Irvine (1961) Moss (1964) Griffin and Sorrie (1964) Williamson (1965) Leck et al (1968) Smithells (1968) Jepson (1969)","journal-title":"McDonald; Record and McKeown"},{"key":"ref_2","article-title":"adjusted for length of gestation during the period from April 1958 to","volume-title":"to that in Fig. 8 except that the maximal number of cases occurred in; and Record, 1966). The incidence of anencephalus in each month was higher in Belfast and the maximal rate was in October, while in Birmingham relatively lower monthly rates occurred and the highest was in November. The analysis of Birmingham anencephalic births by season during various years between 1945 and 1956","year":"1965","unstructured":"adjusted for length of gestation during the period from April 1958 to March 1965 (Leck and Record, 1966). The incidence of anencephalus in each month was higher in Belfast and the maximal rate was in October, while in Birmingham relatively lower monthly rates occurred and the highest was in November. The analysis of Birmingham anencephalic births by season during various years between 1945 and 1956 (Edwards, 1961b) does not permit the calculation of monthly incidence rates, but the observed numbers show a similar trend to that in Fig. 8 except that the maximal number of cases occurred in December. Apart from these differences the seasonal trends in Belfast and Birmingham are very similar."},{"article-title":"Trends in South Wales for 1956-62 (Laurence et al., 1968b) differ in having a peak incidence in March in contrast to November in Belfast, and also no overall winter excess, the winter\/summer ratio","author":"WALES, SouTi","key":"ref_3","unstructured":"SouTi WALES Trends in South Wales for 1956-62 (Laurence et al., 1968b) differ in having a peak incidence in March in contrast to November in Belfast, and also no overall winter excess, the winter\/summer ratio being 0-98 (Fig. 9 and Table IX)."},{"key":"ref_4","article-title":"demonstrated that this part of the United Kingdom has a high incidence of anencephalus, and in his survey of all Belfast births during one year","volume-title":"earlier investigations in Northern Ireland, Stevenson; an anencephalic rate of 4-6 was estimated","author":"It is now apparent that there was an abnormally high incidence in that particular year.","year":"1959","unstructured":"In earlier investigations in Northern Ireland, Stevenson (1959) demonstrated that this part of the United Kingdom has a high incidence of anencephalus, and in his survey of all Belfast births during one year (1957) an anencephalic rate of 4-6 was estimated (Stevenson and Warnock, 1959; British Medical Journal, 1967). It is now apparent that there was an abnormally high incidence in that particular year."},{"key":"ref_5","unstructured":"The present investigation shows that the incidence of anencephaLus in Belfast has been consistently above 3'00 during 1950-66. Estimates of incidence based on deliveries in teaching hospitals, a commonly used source of ascertainment, were demonstrated to be much too high compared with the true community figures. The community surveys conducted to date in the British Isles (Table VII) confirm differences in incidence, Belfast being the highest, although Dublin data (Coffey and Jessop, 1957; Elwood and Warnock, 1969) suggest that the incidence there may be almost as high.","article-title":"The present investigation shows that the incidence of anencephaLus in Belfast has been consistently above 3'00 during 1950-66. Estimates of incidence based on deliveries in teaching hospitals, a commonly used source of ascertainment, were demonstrated to be much too high compared with the true community figures. The community surveys conducted to date in the British Isles (Table VII) confirm differences in incidence, Belfast being the highest, although Dublin data (Coffey and Jessop, 1957; Elwood and Warnock, 1969) suggest that the incidence there may be almost as high"},{"key":"ref_6","article-title":"Many hypotheses have been put forward to explain the epidemiology of anencephalus. A genetic basis has been favoured by the observed increased risk of recurrence in subsequent sibs (Carter and Fraser Roberts","volume-title":"and Laurence, 1968), but the high frequency of discordance in monozygotic twins","author":"Carter, David","year":"1967","unstructured":"Many hypotheses have been put forward to explain the epidemiology of anencephalus. A genetic basis has been favoured by the observed increased risk of recurrence in subsequent sibs (Carter and Fraser Roberts, 1967; Carter, David, and Laurence, 1968), but the high frequency of discordance in monozygotic twins (Record and McKeown, 1951)"},{"key":"ref_7","article-title":"and the lack of fit of pedigree data to Mendelian ratios","year":"1957","unstructured":"and the lack of fit of pedigree data to Mendelian ratios (Penrose, 1957; Yen and MacMahon, 1968; Carter, 1969) argue against any simple genetic explanation. Family studies along the lines suggested by Edwards (1960), Carter (1964),Vogel and Kruger (1967), and Nance (1969) are needed to determine the proportions of affected births to maternal and paternal relatives so that the hypotheses of polygenic, recessive or cytoplasmic inheritance may be tested.","journal-title":"Kruger (1967), and Nance; Yen and MacMahon, 1968; Carter, 1969) argue against any simple genetic explanation. Family studies along the lines suggested by Edwards (1960), Carter (1964), Vogel and"},{"key":"ref_8","first-page":"1","article-title":"Wilson, 1964), some of which will now be considered. The geographical distribution of incidence within the British Isles suggests that anencephalus may be associated with low parental income, hence this malformation should be more frequent in areas where poverty is more common. However, the rates in Bombay","volume-title":"in reported series from the poorer countries of the world are lower than in many more prosperous countries","author":"true","year":"1960","unstructured":"There is evidence that anencephalus is associated with environmental factors (Giroud, 1960; Mellin, 1964; Wilson, 1964), some of which will now be considered. The geographical distribution of incidence within the British Isles suggests that anencephalus may be associated with low parental income, hence this malformation should be more frequent in areas where poverty is more common. However, the rates in Bombay, 1-40 (Kolah, Master and Sangvhi, 1967), Sao Paulo, 0-55 (Stevenson et al., 1966), and in reported series from the poorer countries of the world are lower than in many more prosperous countries."},{"key":"ref_9","unstructured":"An alternative explanation of the lower incidence in the Boston-Irish is that these migrants may have been already at low risk even while resident in Ireland. Although migration is known to be selective (Adams, 1932; Isaac, 1947), this explanation is unlikely as the only substantial groups in Belfast having low rates are social classes 1 and II (Table VIII) who contri-","article-title":"An alternative explanation of the lower incidence in the Boston-Irish is that these migrants may have been already at low risk even while resident in Ireland. Although migration is known to be selective (Adams, 1932; Isaac, 1947), this explanation is unlikely as the only substantial groups in Belfast having low rates are social classes 1 and II (Table VIII) who contri-"},{"key":"ref_10","first-page":"176","article-title":"Aspects of births in the Shatby Hospital, Alexandria","volume":"20","author":"ABUL-EINEN, M.; TOPPOZADA, H.K.","year":"1966","unstructured":"ABUL-EINEN, M., and TOPPOZADA, H. K. (1966). Aspects of births in the Shatby Hospital, Alexandria. Brit. J. prev. soc. Med., 20, 176.","journal-title":"Brit. J. prev. soc. Med"},{"key":"ref_11","article-title":"Ireland and Irish Emigration to the New Worldfrom 1815 to the Famine","author":"ADAMS, W.F.","year":"1932","unstructured":"ADAMS, W. F. (1932). Ireland and Irish Emigration to the New Worldfrom 1815 to the Famine. Yale University Press, New Haven."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1001\/archneur.1962.04210050047005","article-title":"Anencephalus, hydrocephalus, and spina bifida. Epidemiology, with special reference to a survey in Charleston, S","volume":"7","author":"ALTER, M.","year":"1962","unstructured":"ALTER, M. (1962). Anencephalus, hydrocephalus, and spina bifida. Epidemiology, with special reference to a survey in Charleston, S.C. Arch. Neurol. (Chic.), 7, 411.","journal-title":"C. Arch. Neurol. (Chic.)"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1111\/j.1471-0528.1954.tb07507.x","article-title":"The causes and prevention of stillbirths and first week deaths. III. A classification of deaths by clinical cause; the effects of age, parity and length of gestation on death rates by cause","volume":"61","author":"BAIRD, D.; WALKER, J.; THOMSON, A.M.","year":"1954","unstructured":"BAIRD, D., WALKER, J., and THOMSON, A. M. (1954). The causes and prevention of stillbirths and first week deaths. III. A classification of deaths by clinical cause; the effects of age, parity and length of gestation on death rates by cause. J. Obstet. Gynaec. Brit. Emp., 61, 433.","journal-title":"J. Obstet. Gynaec. Brit. Emp"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1136\/bmj.2.5543.3","article-title":"Leading article. Worldwide study of malformations","volume":"2","author":"JOURNAL, BRrISH M.E.D.I.C.A.L.","year":"1967","unstructured":"BRrISH MEDICAL JOURNAL (1967). Leading article. Worldwide study of malformations. Brit. med. J., 2, 3.","journal-title":"Brit. med. J"},{"key":"ref_15","first-page":"135","article-title":"Perinatal mortality survey for County Galway. 18 months","volume":"57","author":"CAHALANE, S.F.; KENNEDY, J.D.; McNICHOLL, B.; O'DWYER, E.","year":"1965","unstructured":"CAHALANE, S. F., KENNEDY, J. D., McNICHOLL, B., and O'DWYER, E. (1965). Perinatal mortality survey for County Galway. 18 months, October 1958, through March 1960. J. Irish med. Ass., 57, 135.","journal-title":"J. Irish med. Ass"},{"key":"ref_16","first-page":"306","volume-title":"The genetics of common malformations. In Second International Conference on Congenital Malformations","author":"CARTER, C. 0","year":"1964","unstructured":"CARTER, C. 0. (1964). The genetics of common malformations. In Second International Conference on Congenital Malformations, New York, 1963, p. 306. International Medical Congress, New York."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1093\/oxfordjournals.bmb.a070671","article-title":"Genetics of common disorders","volume":"25","author":"CARTER, C. 0","year":"1969","unstructured":"CARTER, C. 0. (1969). Genetics of common disorders. Brit. med. Bull., 25, 52.","journal-title":"Brit. med. Bull"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1136\/jmg.5.2.81","article-title":"A family study of major central nervous system malformations in South Wales","volume":"5","author":"DAVID, P.A.; LAURENCE, K.M.","year":"1968","unstructured":"- DAVID, P. A., and LAURENCE, K. M. (1968). A family study of major central nervous system malformations in South Wales. J. med. Genet., 5, 81.","journal-title":"J. med. Genet"},{"key":"ref_19","first-page":"306","article-title":"The risk of recurrence after two children with central-nervoussystem malformations","volume":"1","author":"ROBERTS, F.R.A.S.E.R.; A, J.","year":"1967","unstructured":"-', and FRASER ROBERTS, J. A. (1967). The risk of recurrence after two children with central-nervoussystem malformations. Lancet, 1, 306.","journal-title":"Lancet"},{"key":"ref_20","first-page":"1154","article-title":"Anencephaly. A 6 year study of 367 cases","volume":"103","author":"CASSADY, G.","year":"1969","unstructured":"CASSADY, G. (1969). Anencephaly. A 6 year study of 367 cases. Amer. J. Obstet. Gynec., 103, 1154.","journal-title":"Amer. J. Obstet. Gynec"},{"key":"ref_21","first-page":"41","article-title":"Statistical utilisation of maternity and child welfare records","volume":"5","author":"CHARLEs, E.","year":"1951","unstructured":"CHARLEs, E. (1951). Statistical utilisation of maternity and child welfare records. Brit. J. soc. Med., 5, 41.","journal-title":"Brit. J. soc. Med"},{"key":"ref_22","first-page":"174","article-title":"A study of 137 cases of anencephaly","volume":"11","author":"COFFEY, V.P.; JESSOP, W.J.E.","year":"1957","unstructured":"COFFEY, V. P., and JESSOP, W. J. E. (1957). A study of 137 cases of anencephaly. Brit. J. prev. soc. Med., 11, 174.","journal-title":"Brit. J. prev. soc. 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M.D. thesis, The Queen's University, Belfast."},{"key":"ref_29","article-title":"The incidence of anencephalus in Ireland","author":"ELWOOD, J.H.","year":"1970","unstructured":"ELWOOD, J. H. (1970). The incidence of anencephalus in Ireland. To be published."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/BF02954668","article-title":"Anencephalus in Belfast and Dublin","volume":"2","author":"WARNOCK, H.A.","year":"1969","unstructured":"-, and WARNOCK, H. A. (1969). Anencephalus in Belfast and Dublin. Irish J. med. Sci., Seventh Series, 2, 17.","journal-title":"Irish J. med. Sci., Seventh Series"},{"key":"ref_31","author":"FRtZAL, J.; KELLEY, J.; GUILLEMOT, M.L.; LAMY, M.","year":"1964","unstructured":"FRtZAL, J., KELLEY, J., GUILLEMOT, M. L., and LAMY, M. (1964). Anencephaly in France. Amer. J. hum.","journal-title":"Anencephaly in France. Amer. J. hum"},{"key":"ref_32","article-title":"Classification of Occupations 1966","author":"OFFICE, G.E.N.E.R.A.L.R.E.G.I.S.T.E.R.","year":"1966","unstructured":"GENERAL REGISTER OFFICE (1966). Classification of Occupations 1966. H.M.S.O., London."},{"key":"ref_33","article-title":"Causes and morphogenesis of anencephaly","volume-title":"Ciba Foundation Symposium on Congenital Malformations","author":"GIRouD, A.","year":"1960","unstructured":"GIRouD, A. (1960). Causes and morphogenesis of anencephaly. In Ciba Foundation Symposium on Congenital Malformations, ed. Wolstenholme, G. E. W., and O'Connor, C. M. P. 199. Churchill, London."},{"key":"ref_34","first-page":"153","article-title":"Declining incidence of central nervous system anomalies in New York State","volume":"16","author":"GrrrELsoHN, A.M.; MILHAM, S.","year":"1962","unstructured":"GrrrELsoHN, A. M., and MILHAM, S. (1962). Declining incidence of central nervous system anomalies in New York State. Brit. J. prev. soc. 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Maternal health in early pregnancy and congenital defect. Final report of a prospective inquiry. Brit. J. prev. soc. Med., 15, 154.","journal-title":"Brit. J. prev. soc. Med"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/S0140-6736(51)93354-5","article-title":"Seasonal incidence of congenital malformations of the central nervous system","volume":"1","author":"McKEowN, T.; RECORD, R.G.","year":"1951","unstructured":"McKEowN, T., and RECORD, R. G. (1951). Seasonal incidence of congenital malformations of the central nervous system. Lancet, 1, 192.","journal-title":"Lancet"},{"key":"ref_51","first-page":"211","article-title":"Anencephalus, spina bifida, and hydrocephalus. Incidence related to sex, race, and season of birth, and incidence in siblings","volume":"7","author":"MACMAHoN, B.; PUGH, T.F.; INGALLs, T.H.","year":"1953","unstructured":"MACMAHoN, B., PUGH, T. F., and INGALLs, T. H. (1953). Anencephalus, spina bifida, and hydrocephalus. 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