Carolyn L. Olsen

THE EFFECTS OF PRENATAL DIAGNOSIS, POPULATION AGEING, AND CHANGING FERTILITY RATES ON THE LIVE BIRTH PREVALENCE OF DOWN SYNDROME IN NEW YORK STATE, 1983–1992

The incidence of Down syndrome (DS) at conception is highly dependent on the maternal age distribution and age‐specific pregnancy rates. The live birth prevalence of DS reflects these factors and fetal deaths. This study examined DS live birth prevalence from 1983 to 1992 in New York State and analysed the effects of demographic changes and prenatal diagnosis use on the observed live birth prevalence. Expected DS live birth prevalence without prenatal diagnosis was calculated and compared with observed. Data were obtained from birth defects registries, vital records, and population data maintained by the New York State Department of Health. Over time, DS live birth prevalence was stable at about 10·4 per 10 000 live births. The percentage and number of women in the population above age 30 increased, as did birth rates among these women. Birth rates among younger women decreased. The proportion of DS babies born to women aged 35 and over increased from 27·1 to 34·1 per cent. Use of prenatal diagnosis by this age group ranged from 39·6 to 43·2 per cent, and increased steadily from 1·8 to 4·3 per cent among women under 35. Detection of DS fetuses increased from 82 in 1985 to 233 in 1992. Without prenatal diagnosis, DS live birth prevalence in 1992 would have reached 15·3 per 10 000 live births compared to the 10·2 observed. Prenatal diagnosis has prevented an increase in DS live birth prevalence but has not been sufficient to reduce live birth prevalence significantly.

First Year-of-Life Mortality Among Infants with Oral Clefts: New York State, 1983–1990

This study examined the mortality experience of children with oral clefts using the New York State Congenital Malformations Registry. Infants born in the years 1983 to 1990 to New York residents, diagnosed with an oral cleft and matched to their birth certificate were included in the analysis. Children with oral clefts were compared to a sample of live births from the years 1983 to 1990 without malformations. Children with cleft palate without additional malformations had a statistically nonsignificant adjusted risk of 1.2 when compared to children with no malformations. Children with cleft lip with or without cleft palate had a 1.1 adjusted risk. However, 35% of children with oral clefts had associated malformations and experienced much higher mortality. Children with oral clefts should be carefully evaluated for additional malformations; if none are found, their mortality appears not to be elevated.

Down Syndrome: Interaction between Culture, Demography, and Biology in Determining the Prevalence of a Genetic Trait

The incidence of Down syndrome (DS) at conception is highly dependent upon the maternal age distribution and age-specific pregnancy rates. Live-birth prevalence of DS reflects these factors and fetal deaths. Since the introduction of prenatal diagnosis in the early 1970s, the role of fetal deaths in the equation has increased. Between 1920 and the early 1980s, DS live-birth prevalence decreased in many populations due to declining fertility rates, particularly among older women. In the late-1970s the trend reversed, as the median age of populations and birth rates among older women steadily increased. This paper illustrates these interactions using data we have analyzed for New York State (NYS) and comparative data obtained from the literature. Between 1983 and 1997 DS live-birth prevalence in NYS remained stable at about 9.9 per 10,000 live births. The number of prenatal tests performed increased by 158%, and the number of DS fetuses detected prenatally more than quadrupled. Fertility rates of women aged 35-49 continued to increase. The proportion of DS cases born to these older mothers increased from 23% in 1985 to 43% in 1997. We estimated that without prenatal diagnosis, DS live-birth prevalence would have been 17.0 per 10,000 live births by 1995. Cultural factors influence demographic trends, birthing technologies, physician practices, and womens decision-making regarding prenatal screening and diagnosis for DS.

Care of Diabetic Patients by Optometrists in New York State

Objective This study was undertaken to learn about the involvement of optometrists in the eye care of diabetic patients in New York and to collect baseline data for planning intervention programs in diabetic eye disease. Research Design and Methods This study was conducted by a mail survey being sent to all optometrists in New York whom we could identify through state sources (n = 2270). Three follow-up mailings were conducted. Results Eighty-six percent who received our mailing responded, 87%of whom reported that they see diabetic patients. Analysis was confined to this 87%. Routine retinal examinations were provided by 68% of the respondents who see diabetic patients, 62% of whom dilate the pupils. Sixty-eight percent who see diabetic patients diagnose retinopathy solely by their own examination, and 60% of these dilate. Follow-up of retinopathy was provided by 15% of optometrists who see diabetic patients, 90% of whom dilate the pupils of their diabetic patients. Twenty-five percent of respondents who see diabetic patients refer them to an ophthalmologist for diagnosis of retinopathy, and 67% refer all retinopathy patients to an ophthalmologist for follow-up. Although 91% of respondents recommended eye examinations at least annually for diabetic patients, only 68% specifically recommended annual examinations through dilated pupils. Those who dilate were significantly more likely to recommend annual dilated examinations than those who do not dilate, regardless of practice setting. Conclusions These findings indicate that optometrists as a group see many diabetic patients. Intervention strategies should include increased emphasis on the use of dilation when examining diabetic patients and annual dilated retinal examinations.