Estimating the prevalence of fetal alcohol syndrome a summary pdf

Some of this variation is a valid reflection of the differences in FAS rates between populations, each of which may possess a number of unique risk factors, especially variations in maternal drinking behavior. But variance in rates between studies can often merely be a function of the different research methods used to study the problem.

The following section reviews various studies and their findings, by method and by population see table 1. Passive Method. United States. CDC Chavez et al. American Indian.

Alaska, non-native. Egeland et al. Alaska Native. North Dakota. Burd et al. Various studies avg. Western World. Abel and Sokol United States and Canada. United States and other countries. Abel White American. Plains Indian. May et al. Southwestern Plains Indian. Southwestern Indian. Washington State. Clarren et al. NOTE: avg. This system uses hospital discharge data from 10 to 30 percent depending on the year of all births in the country. Based on this system, the estimated rate of FAS at birth was 2.

Therefore, a rate of one per 1, would mean that, on average, one FAS child is born among each 1, babies in the given geopolitical area e. In the United States in , there were 3,, births. Similarly a rate of 0. Increased rates of 3. The researchers questioned, however, whether this increase reflected a true increase in FAS births or better reporting within the system. The estimated rates per 10, and per 1, were 6. The rates produced by this passive system are much lower than those produced by any other method.

Local studies that have used passive methods e. Including partial FAS, the rate was 2. In Alaska, a capture recapture study used multiple sources of records, including data from hospitals, pediatricians, birth and death certificates, Alaska Native Health Service records, and genetics, disabilities, and learning programs. Researchers reported that the FAS rate for for the non-Native population was 0.

In North Dakota, Burd and colleagues reported rates of 1. Finally, in a recent study from New Zealand that used passive methods, pediatricians were asked to complete a postal survey designed to compile data about children with alcohol-related birth defects. For , the rate of FAS among children less than ten years of age was reported as 0.

This review of FAS rates produced by passive systems clearly indicates that very low rates of FAS are reported within the large populations studied, particularly for non-Indian and non-Native populations, and higher rates are reported for American Indians and Alaska Natives. A substantial number of studies of this type have been conducted. Abel and Sokol s review of 18 clinic-based, mostly prospective studies reported an average rate of FAS for the western world of 1.

Abel and Sokol later reviewed 20 prospective, clinic-based studies including many of the same studies reviewed in , and reported a lower rate of 0. By Abel , a total of 35 prospective, clinic-based studies had been conducted in at least 40 sites in the western world including the United States [12 studies] , the United Kingdom [5 studies] , Australia [4 studies] , Spain [3 studies] , and Canada, Denmark, France, Italy, the Netherlands, Portugal, Sweden, and Switzerland combined [16 studies].

Many of the studies that were performed outside of the United States were carried out among middle class, Caucasian subjects. Only three of the foreign studies reported any FAS cases, and these three reported only four cases total, producing a very low overall average rate, and median and modal rates of FAS per study of zero.

Abel concluded that FAS occurred considerably more often at some sites than at others, , estimating the rate for the western world at 0. This has been referred to as the American Paradox since it is likely linked to the fact that the United States has both more abstainers and more heavy drinkers compared with France and many other parts of the western world Abel a , b.

Therefore, it is not the prevalence of all drinkers or the amounts that they drink over a long period in European countries, but rather the proportion of drinkers who consume substantially large quantities in a short time period that elevates the frequency of occurrence of the major and most severe FAS symptoms, which make up the diagnosis of FAS. All but four of the U. Calculations based on data from another aggregation of these studies 28 studies indicated that FAS occurred in 4.

Other research projects used prospective, clinic-based studies to document all levels of alcohol-related anomalies from severe to mild present in cohorts of children born to mothers who were initially recruited when they were receiving prenatal and other obstetric care. At study sites in Seattle Streissguth et al. They have periodically compared the children on measures of physical growth and development, dysmorphology, and psychological development over time e. By grouping the data in various ways to describe the lesser effects of prenatal exposure to alcohol e.

One longitudinal study from this body of literature Sampson et al. Some studies in other countries in the western world have found a similar pattern of symptoms linked to prenatal alcohol consumption as that found in American studies of ARBD and ARND.

For example, French researchers Rostand et al. On the other hand, a study in Australia by Walpole and colleagues failed to show any significant relationship between low to moderate maternal alcohol intake and fetal outcome.

Therefore, in spite of the similar pattern of anomalies associated with low and moderate levels of alcohol consumed during pregnancy, studies outside the United States continue to illustrate the American Paradox described by Abel a , where low to moderate use of alcohol defined liberally as less than 21 drinks per week by Rostand and colleagues [] does not result in FAS or symptoms as severe as those reported in U.

Active case ascertainment methods were first used among American Indian populations May et al. Similar methods have been used in epidemiological studies of more than 24 American Indian and Alaskan and Canadian Native communities May et al. Until recently, active case ascertainment methods had been used exclusively among American Indians, and primarily among small, well-defined populations.

Two recent reports from large community studies using active case finding and ascertainment methods were conducted among first graders in a municipality in South Africa May et al. Active case ascertainment generally yields the highest number of cases and rates of FAS for a particular population.

Although the same clinical, diagnostic criteria are used as in the clinic-based studies, the difference in prevalence rates is related to the selection of children who are presented to the clinicians and the age at which clinical contact is made. Apparently, many children who have FAS are not seen in clinics where the proper diagnosis of FAS can be made, or at a time when it can be made.

For example, Clarren and colleagues reported that six of seven first graders who were diagnosed with FAS in their study had never before received a FAS diagnosis. Similarly, Little and colleagues had previously reported that of 40 newborns in a large hospital in Texas who were strong candidates for a FAS diagnosis i.

Age at examination is therefore a very important consideration in establishing the true prevalence of this disorder. Most active case ascertainment studies have been conducted among American Indians in very high-risk communities.

Of these three approaches, clinic-based studies are the most common, followed by passive systems, and then active case ascertainment. Passive systems are generally the least expensive, followed by clinic-based studies; active case ascertainment studies are frequently the most costly and time intensive Stratton et al.

Researchers using passive systems to study FAS epidemiology use existing record collections in a particular geographical catchment area e. Many recent passive surveillance studies have used multiple types of records to identify as many cases of alcohol-related anomalies as possible, since a case of FAS is frequently documented in more than one place e.

These multiple records approaches are referred to as capture-recapture methods Egeland et al. In the context of FAS, some researchers e. Without providing a detailed explanation of the conventional use of these terms in other areas of epidemiology i. The authors of this article and their colleagues have used the aforementioned terms i. Because FAS can exist theoretically in a fetus for up to 7 months prior to birth, the following question arises: When is FAS considered to be a new case?

Because frequent spontaneous abortions occur among alcohol-abusing women, the prevalence of FAS during certain months of pregnancy may actually be much higher than the number of FAS cases recorded at birth. The major advantage of passive methods is that they efficiently utilize existing health care systems, programs, and records that are already funded by other sources.

This approach is therefore relatively inexpensive and easier to undertake than some other research methods. But there are also major disadvantages. FAS, ARBD, and ARND, however, are complex, involving multiple indicators of physiology, development, and behavior, many of which are not obvious at all or are at least more difficult to identify at particular ages e.

Therefore, passive systems, which generally depend on the diagnoses of many hundreds of non-specialist physicians, educators, and other service providers who may miss FAS symptoms because of the circumstances of examination or the age at which the child is presented , lack the rigor and consistency of diagnoses that characterize other systems. Furthermore, passive systems depend on a variety of registries for complete and consistent records and are therefore vulnerable to the many contingencies that affect the quality of data in institutions where these data are collected.

Clinic-based studies conducted throughout the United States and the world have provided much of the current knowledge about the epidemiology of FAS and other alcohol-related disorders Stratton et al. This prospective research lends itself to a consistent design and rigorous methodology that can control for many of the problems inherent in the passive methods. Clinic-based studies are generally conducted in prenatal clinics of large hospitals where researchers can collect data from mothers as they pass through the various months of their pregnancies.

Researchers collect information from pregnant women about their diets, jobs, social interactions, psychological health, and alcohol, tobacco, and other drug use using standard screening instruments and specimen samples. Control groups are easy to obtain, since all consenting women in the clinics are screened. Generally one-half to a very substantial majority of women will report abstaining, providing an adequate comparison group.

Due to the prospective nature of these designs, researchers are generally able to examine the infants at birth and sometimes for some months postpartum and match the maternal behaviors with the pregnancy outcomes. Clinic-based studies have many advantages: the opportunity to gather maternal history data; the opportunity to study a large number of pregnancies with various levels of alcohol and other drug exposure; health services are provided, offering incentives for participants; and the prospective design provides greater control and rigor in measuring most of the important variables.

However, there are also disadvantages. Subjects are self-selected. The women at highest risk for FAS offspring are less likely to attend prenatal clinics regularly, and many do not attend at all, making access to the very highest risk cases less regular or impossible with these methods. A second problem is that many, if not most, of the clinic-based studies conducted in the United States have been carried out in publicly funded hospitals and clinics where disadvantaged populations predominate.

Therefore, clinic studies and the data obtained may overrepresent the prevalence of FAS and the characteristics of these selected populations, and underrepresent middle- and upper-class populations.

Third, since FAS is not most accurately diagnosed at birth, but between the ages of 3 and 12 years, these studies may also underestimate the prevalence of FAS in the population studied Aase ; Stratton et al.

This approach to studying FAS, like the passive surveillance method, focuses on large populations in particular geographical or catchment areas, such as schools, towns, and Indian reservations. Active case ascertainment studies are unique in that they actively seek, find, and recruit children who may have FAS within the population under study.

Once researchers set the criteria for referral to clinical examination and testing, and establish a referral network and referral procedures, clinical specialists examine possible cases and assess the physical growth and development, dysmorphology, and psychosocial characteristics of the children for a final diagnosis.

The active case ascertainment methods have at least three advantages. One, the primary focus is on finding children with FAS at appropriate ages for accurate diagnosis by clinical specialists. Two, active, effective, and comprehensive outreach in a large general population is most likely to uncover children with FAS and alcohol-abusing mothers at the highest risk.

Three, by studying entire communities or populations, this method can eliminate much selectivity and generally ensure wide representation. Therefore, an efficient active case ascertainment approach may produce the most complete access to children with FAS and the most complete assessment of the prevalence and population-based characteristics of FAS in a particular population.

There are also substantial disadvantages that can negate the benefits of this approach. First, such research is very labor intensive, time consuming, and costly see Stratton et al. Second, studies of this type require cooperation from many non-researchers in the study population e. If a vital community constituency does not support a study, case finding may be incomplete or selective, resulting in underrepresentation of the prevalence or a skewed understanding of the true characteristics of the problem.

High levels of cooperation with research on stigmatized topics such as FAS and maternal drinking are often difficult to achieve. Third, access to particular populations may be selective, and frequently only high-risk populations have been studied using these methods. In other words, these studies have been most frequently carried out where there are a large number of FAS cases to be found. If such selective populations are studied and these findings projected to the general population, then the prevalence of FAS may be overestimated.

Estimates of the prevalence of FAS vary greatly from population to population and from study to study. Some of this variation is a valid reflection of the differences in FAS rates between populations, each of which may possess a number of unique risk factors, especially variations in maternal drinking behavior. But variance in rates between studies can often merely be a function of the different research methods used to study the problem. The following section reviews various studies and their findings, by method and by population see table 1.

NOTE: avg. This system uses hospital discharge data from 10 to 30 percent depending on the year of all births in the country.

Based on this system, the estimated rate of FAS at birth was 2. The researchers questioned, however, whether this increase reflected a true increase in FAS births or better reporting within the system. The estimated rates per 10, and per 1, were 6. The rates produced by this passive system are much lower than those produced by any other method.

Local studies that have used passive methods e. In Alaska, a capture-recapture study used multiple sources of records, including data from hospitals, pediatricians, birth and death certificates, Alaska Native Health Service records, and genetics, disabilities, and learning programs.

Researchers reported that the FAS rate for — for the non-Native population was 0. In North Dakota, Burd and colleagues reported rates of 1. Finally, in a recent study from New Zealand that used passive methods, pediatricians were asked to complete a postal survey designed to compile data about children with alcohol-related birth defects.

Other facial Methods anomalies have also been reported such as maxillary hypoplasia Audit population and epicanthal folds. For the purpose of this audit, mention of any Records of all live births in Victoria, , were available one of the classical facial features of FAS fulfilled the criteria for for audit. Chromosomal likely to be poor. We also included records of three reported cases alcohol use during pregnancy and potentially a risk factor.

If alcohol use was specified heart anomalies. In addition, searching the PDCU records for as being less than or equal to two drinks per day then this was evidence of maternal alcohol use using ICD code F The CDC guidelines on alcohol use during 28 live birth records between and Prior to , this pregnancy differ from NHMRC guidelines and recommend information was not routinely collected. None of these babies abstinence during pregnancy.

They also recommend that in the were reported as having microcephaly. The total number of records absence of confirmation of alcohol use but in the presence of fulfilling the selection criteria for audit was and came from all other factors, a diagnosis of FAS should not be excluded.

The medical record was also checked for Selection Initial audit Records not Final audit hospital admissions relating to alcohol consumption as evidence criteria population accessed population of alcohol exposure.

Maternal alcohol 28 2 26 use PCDU 1. FAS cases. These three records were audited to VOL. Article confirm the report to the VBDR. Possible FAS cases. Any cases having a two of CNS group. If these cases are included, the prevalence rises to 0. Unable to categorise. These cases had several features of FAS for alcohol consumption while pregnant. For example, one case such as microcephaly and small for gestational age. However, had microcephaly and was less than the third percentile for birth in these cases there was no information related to either alcohol weight but had alcohol in the prenatal records marked as less than use or abstinence.

Another had microcephaly, 4. Not FAS. All remaining cases. This group consisted of those heart anomalies and dysmorphic features with no description of with microcephaly, but without two of the associated co- those features. Indeed, many 0. This group also included those identified based on maternal alcohol consumption but lacking other co-morbidities. This Victorian project has provided additional information Results for a revised estimate of FAS prevalence in Victoria of 0.

From the Birth 1, live births instead of 0. No additional confirmed cases of recommendations for alcohol consumption in pregnancy. This FAS were found. Several different approaches have been used to estimate how many persons are living with FASDs in the population.

FASDs include several diagnoses related to exposure of the baby to alcohol during pregnancy. More specifically, fetal alcohol syndrome FAS is the most involved diagnosis, used when several physical and developmental abnormalities are present see Facts about FASDs.

Using medical and other records, CDC studies have identified 0. People with severe problems, such as profound intellectual disability, have much higher costs. Alcohol use and binge drinking among pregnant people in the United States, — Trends in Alcohol Use Among Pregnant Women in the United States, — A report published in the American Journal of Preventive Medicine found that both current alcohol use and binge drinking among pregnant women aged 18—44 years in the United States increased slightly from to Current drinking having at least one drink of any alcoholic beverage in the past 30 days increased from 9.