Mathias B. Forrester

Epidemiology of abdominal wall defects, Hawaii, 1986–1997

The various types of abdominal wall defects are considered to differ in their etiologies, a hypothesis suggested by differences in their epidemiologies. This study examined the impact of selected demographic factors on abdominal wall defects (omphalocele, gastroschisis, and body stalk anomaly) included in a birth defects registry in Hawaii from 1986-1997. The total prevalence for the various defects were: omphalocele (2.76 per 10,000 births, 95% confidence interval (CI), 2.14-3.50), gastroschisis (3.01, 95% CI, 2. 36-3.77), and body stalk anomalies (0.32, 95% CI, 0.14-0.64). The prevalence increased over the 12-year period for both omphalocele (P = 0.052) and gastroschisis (P = 0.008). Women less than age 20 were at increased risk for a gastroschisis-affected pregnancy, while those age 40 and over were disproportionately more likely to have an omphalocele-affected pregnancy. Pacific Islanders had the lowest risk for omphalocele, whereas Far East Asians were least likely to have gastroschisis. Omphalocele rates were lower outside metropolitan Honolulu, while place of residence did not significantly impact gastroschisis risk. The 1-year survival rate was higher for gastroschisis than for omphalocele (88.5% and 70.7%, respectively), while none of the infants with body stalk anomalies was live-born. The results of this study tend to support the hypothesis of differing etiologies for the studied abdominal wall defects.

Descriptive epidemiology of oral clefts in a multiethnic population, Hawaii, 1986-2000.

Objective To describe the relationship between oral clefts and demographic and clinical factors in Hawaii. Methods Data were obtained from a birth defects registry and included all infants and fetuses with oral clefts delivered during 1986 through 2000. Subjects were categorized as total, isolated, and nonisolated cleft lip with or without cleft palate (CL±P) or cleft palate without cleft lip (CP). Results There were 352 total subjects of CL±P and 192 total subjects of CP with corresponding rates per 10,000 live births of 12.5 for CL±P and 6.8 for CP. Total, isolated, and nonisolated CL±P rates demonstrated no clear pattern by maternal age. The total and nonisolated CP rates tended to be higher among older maternal age groups. The total CL±P rate was higher among Far East Asians, Pacific Islanders, and Filipinos than among whites. The total CP rate was higher among Far East Asians and Pacific Islanders than among whites, whereas the rate for Filipinos was lower than for whites. The total CL±P rate was substantially lower among females (rate ratio 0.62, 95% confidence interval [CI] = 0.49 to 0.77) and the total CP rate substantially higher among females (rate ratio 1.52, 95% CI = 1.13 to 2.06). Both CL±P and CP were more common with lower birth weight and gestational age among the total, isolated, and nonisolated groups. Conclusions Oral cleft risk was associated with maternal race/ethnicity, sex, birth weight, and gestational age. Although some of the observed associations were consistent with the literature, others were not.

Descriptive epidemiology of anotia and microtia, Hawaii, 1986-2002.

ABSTRACT  The objective of this investigation was to describe the epidemiology of anotia and microtia with respect to various factors. The cases studied were all infants and fetuses with anotia or microtia identified by a population‐based birth defects registry in Hawaii. The anotia and microtia rates were determined for selected factors and comparisons made among the subgroups by calculating the rate ratio (RR) and 95% confidence interval (CI). A total of 120 cases were identified, for a rate of 3.79 per 10 000 live births. The anotia and microtia rate increased during 1986–2002, although the trend was not significant (P = 0.715). Of 49 specific structural birth defects examined, four were found to be significantly more common in the presence of anotia and microtia. When compared with Caucasians, the anotia and microtia rates were higher among Far East Asians (RR 1.79, 95% CI 0.89–3.68), Pacific Islanders (RR 2.26, 95% CI 1.24–4.32), and Filipinos (RR 2.34, 95% CI 1.23–4.64). The defects were less common among females (RR 0.64, 95% CI 0.43–0.93) and more common with multiple birth (RR 3.72, 95% CI 1.66–7.33), birth weight < 2500 g (RR 3.35, 95% CI 2.04–5.30), and gestational age <38 weeks (RR 2.27, 95% CI 1.49–3.40). In conclusion, the rate for anotia and microtia increased in Hawaii during the study period. The rates for only a few structural birth defects were substantially greater than expected in association with anotia and microtia. Anotia and microtia rates varied significantly according to maternal race/ethnicity, infant sex, plurality, birth weight, and gestational age.

First-year mortality rates for selected birth defects, Hawaii, 1986-1999

Birth defects have been the leading cause of infant death in the United States for over the last decade. However, there is little population‐based data on the first‐year mortality rates for many specific birth defects and the factors that may affect these mortality rates. This investigation examined the first‐year mortality rates for 54 selected birth defects of various organ systems in Hawaii during 1986–1999 using data from a population‐based birth defects registry and evaluated the impact of the presence of chromosomal abnormalities and other structural birth defects and the year of delivery on the mortality rates. Mortality rates varied widely by defect, being highest for anencephaly (100%), trisomy 13 (82%), and trisomy 18 (74%), while no first‐year deaths were reported for glaucoma, bladder exstrophy, and persistent cloaca. The majority (36 of 54 or 67%) of the birth defects had a mortality rate of less than 25%. Among the 51 structural birth defects, 38 (75%) had higher first‐year mortality rate for cases with chromosomal abnormalities and 42 (82%) had higher first‐year mortality rates for cases with other major structural birth defects. The mortality rate among 1986–1992 deliveries was higher than the mortality rate among 1993–1999 deliveries for 37 (69%) of the 54 birth defects. This study indicates that first‐year mortality rates vary widely by type of birth defect, although the mortality rate for the majority of birth defects is relatively low. The presence of a chromosomal abnormality or other structural birth defect increases the mortality rate, and mortality rates for the majority of birth defects have declined in Hawaii during the study period.

Birth defects prevalence among infants of Persian Gulf War veterans born in Hawaii, 1989-1993.

BACKGROUND Gulf War veterans (GWVs) have expressed concern about possible teratogenic exposures. However, epidemiologic studies on birth defects prevalence among their progeny have been limited to military hospitals, anomalies diagnosed among newborns, or self-reported data. To measure the prevalence of selected birth defects among infants of GWVs and nondeployed veterans (NDVs) in Hawaii, using birth defects surveillance records. METHODS Personal identifiers of 684,645 GWVs and 1,587,102 NDVs and their families were matched against birth certificate records of 99,545 live births reported to the State of Hawaii Department of Health between 1989 and 1993 to identify births to military personnel. These births were matched with records from the Hawaii Birth Defects Program. RESULTS A total of 17,182 military infants (3,717 GWV infants and 13,465 NDV infants) were identified. Of these, 367 infants (2.14/100 live births) were identified with one or more of 48 major birth defects diagnoses. The prevalence of the 48 birth defects were similar for GWV and NDV infants during the prewar and postwar periods, and among GWV infants who were conceived before and after the Gulf war. CONCLUSIONS The results must be interpreted with caution because of the small number of affected infants in each birth defects category. This study demonstrated the feasibility of measuring birth defects prevalence among military infants through multiple data linkage. Further, it included live births to parents who had separated from the military, births in civilian hospitals, and birth defects diagnosed through the first year of life.

Prenatal diagnosis and elective termination of Down syndrome in a racially mixed population in Hawaii, 1987-1996.

The impact of demographic factors on the prenatal diagnosis and elective termination of Down syndrome in Hawaii between 1987 and 1996 were examined. Data were obtained from a population‐based birth defects registry and included 306 Down syndrome cases. 131 (43 per cent) of the cases were prenatally diagnosed. Of the prenatally diagnosed cases, 110 (84 per cent) were electively terminated. Advanced maternal age or having a maternal serum alpha‐fetoprotein screen performed increased the probability of having an affected pregnancy prenatally diagnosed and electively terminated. Far East Asians were substantially more likely to have an affected pregnancy prenatally diagnosed and electively terminated. Pacific Islanders and Filipinos were less likely to have cases prenatally diagnosed and electively terminated. Prenatally diagnosed and electively terminated Down syndrome cases had disproportionately fewer additional birth defects than live births or fetal demises, suggesting that for many of the electively terminated cases additional birth defects may not have been identified. This implies that the elective termination of Down syndrome‐affected pregnancies may influence not only the Down syndrome prevalence but also that of other birth defects. Copyright

Pregnancy outcome and prenatal diagnosis of sex chromosome abnormalities in Hawaii, 1986-1999.

Sex chromosome abnormalities such as Turner syndrome, Klinefelter syndrome, triple X syndrome, and 47,XYY can be prenatally diagnosed and electively terminated. This investigation examined the pattern of pregnancy outcome of prenatally and postnatally diagnosed sex chromosome abnormalities in Hawaii during 1986–1999 and calculated prenatal diagnosis and subsequent elective termination rates for various factors. Data were obtained from a statewide population‐based birth defects registry. The study included 205 detected sex chromosome abnormality cases of which 93 (45%) were live births, 18 (9%) late fetal deaths, 37 (18%) early fetal deaths, and 57 (28%) elective terminations. Pregnancy outcome distribution varied by type of sex chromosome abnormality. Prenatal diagnosis was reported for 132 (64%) of the cases, of which 46 (35%) were subsequently electively terminated. Eleven cases were elective terminations where the sex chromosome abnormality was diagnosed after delivery. Elective termination rates subsequent to prenatal diagnosis differed by sex chromosome abnormality, being highest for 45,X (54%), followed by 47,XXY (46%), 47,XYY (29%), and 47,XXX (17%). Although prenatal diagnosis rates increased significantly over the time period (P = 0.006), the subsequent elective termination rate declined slightly, albeit the trend was not statistically significant (P = 0.440). The prenatal diagnosis rate was highest for the 35–39‐year maternal age group, although this age group did not have subsequent elective termination rates higher than other maternal age groups. Pregnancy outcome distribution and prenatal diagnosis and subsequent elective termination of sex chromosome abnormalities appeared to depend on the type of sex chromosome abnormality, year of delivery, and maternal age.

Prenatal Diagnosis and Elective Termination of Neural Tube Defects in Hawaii, 1986–1997

Objective: To determine the influence of various factors on the prenatal diagnosis and elective termination of neural tube defects (NTDs) in Hawaii in 1986–1997. Methods: Data from a birth defects registry were analyzed and included 245 cases. Results: 74% of the cases were prenatally diagnosed and 48% were terminated. Anencephaly was more likely to be prenatally diagnosed and electively terminated than spina bifida or encephalocele. Other factors such as maternal age, race/ethnicity, place of residence, and elevated maternal serum α-fetoprotein influenced the prenatal diagnosis and/or elective termination of NTD-affected pregnancies. However, a given factor may influence prenatal diagnosis and elective termination in different ways. Conclusions: Various diagnostic and demographic factors can influence the prenatal diagnosis and the subsequent termination of NTD-affected pregnancies.

Impact of excluding cases with known chromosomal abnormalities on the prevalence of structural birth defects, Hawaii, 1986-1999.

Chromosomal abnormalities are more common in the presence of structural birth defects. However, much of the literature have only provided chromosomal abnormality rates for one or a few structural birth defects at a time. This study calculated the chromosomal abnormality rates for a number of structural birth defects using data from the Hawaii Birth Defects Program (HBDP) for deliveries during 1986–1999 and evaluated the impact of exclusion of cases with chromosomal abnormalities when calculating birth prevalence. The chromosomal abnormality rates were highest for endocardial cushion defect (40%) and omphalocele (27%), while no chromosomal abnormalities were reported for pyloric stenosis, persistent cloaca, and deficiency of lower limbs. The majority of chromosomal abnormality rates fell within a certain range, with 32 (63%) of the birth defect categories having chromosomal abnormality rates of 5–15%. The chromosomal abnormality rates also tended to be higher for multiple than for isolated cases. For three of the structural birth defects (ventricular septal defect, atrial septal defect, endocardial cushion defect), the birth prevalence of the defect, when cases with a chromosomal abnormality were excluded, was significantly lower than the birth prevalence that included those cases. Chromosomal abnormality rates varied by type of structural birth defect and presence of other major structural birth defects. For at least several structural birth defects, exclusion of cases with chromosomal abnormalities significantly underestimated the birth prevalence. This underestimation may be important, depending on the purpose of the analysis.

Impact of demographic factors on prenatal diagnosis and elective pregnancy termination because of abdominal wall defects, Hawaii, 1986-1997

Objective: The intent of this study was to investigate the impact of various demographic factors on the antenatal diagnosis and elective termination of abdominal wall defect pregnancies. Method: Data were obtained from a birth defects registry in Hawaii between 1986 and 1997. Results: The antenatal diagnosis rate was higher for gastroschisis than for omphalocele (76 vs. 60%). However, gastroschisis pregnancies were substantially less frequently electively terminated than omphalocele pregnancies (8 vs. 29%). Factors such as year of diagnosis and delivery, maternal age, race/ethnicity, residence, and maternal serum α-fetoprotein screening affected the prenatal diagnosis and/or elective termination of both omphalocele and gastroschisis pregnancies, but frequently in different ways. Conclusion: This investigation determined that antenatal diagnosis and elective termination varied with the type of abdominal wall defect and selected demographic factors.