The changing epidemiology of neural tube defects. United States, 1968-1989.

OBJECTIVE--To describe the recent trends and epidemiologic characteristics of neural tube defects in the United States. RESEARCH DESIGN--Ongoing surveillance data. SETTING--Two birth defect surveillance systems: the nationwide Birth Defects Monitoring Program and the Metropolitan Atlanta (Ga) Congenital Defects Program for 1970 through 1989 and 1968 through 1989, respectively. PARTICIPANTS--Between 1970 and 1989, using discharge diagnoses of approximately 1 million live-born and stillborn infants per year, the Birth Defects Monitoring Program identified 15,503 cases of spina bifida and anencephaly. Between 1968 and 1989, using discharge diagnoses and clinical records until age 1 year of 38,000 infants per year, the Metropolitan Atlanta Congenital Defects Program identified 800 cases of spina bifida and anencephaly. INTERVENTIONS--None. MEASUREMENTS/MAIN RESULTS--Nationwide, neural tube defect rates have declined from 1.3 per 1000 births in 1970 to 0.6 per 1000 births in 1989. In Atlanta, neural tube defect rates have declined from 2.0 per 1000 births in 1968 to 0.6 per 1000 births in 1989. Several changes in the epidemiologic characteristics of neural tube defects were observed: (1) the proportion of spina bifida cases has increased; (2) the proportion of neural tube defect cases compared with the proportion of other unrelated defects has increased; (3) the race ratio of whites to other races for isolated neural tube defect cases has declined in Atlanta; and (4) the rate of isolated neural tube defects in females has also decreased. CONCLUSIONS--The declining rates of neural tube defects can be partially explained by increased widespread prenatal diagnostic techniques, strongly suggesting the role of environmental factors in neural tube defects. In particular, the use of multivitamins and folic acid to prevent the occurrence of neural tube defects needs further evaluation. Nevertheless, the changing clinical and epidemiologic characteristics of cases over time points to the etiologic heterogeneity of these conditions.     

Increasing prevalence of hypospadias in Western Australia, 1980-2000.

OBJECTIVES: Hypospadias, a common birth defect, has shown widespread variation in reported rates and temporal trends across countries over the last 30 years. The aim of this study was to determine the prevalence and trends of hypospadias in an Australian population. DESIGN: Population-based study of all male infants born in Western Australia (WA) between 1980 and 2000 diagnosed with hypospadias and notified to the WA Birth Defects Registry. MAIN OUTCOME MEASURES: Prevalence of hypospadias, birth outcome and association with other congenital anomalies, stratified by degree-of-severity. RESULTS: 1788 cases of hypospadias were registered in WA in 1980-2000 with an overall prevalence of 34.8 (95% confidence interval (CI): 33.2 to 36.4) cases per 10 000 births. The prevalence increased by 2.0% per annum (95% CI: 1.2% to 2.8%) from 27.9 in 1980 to 43.2 per 10 000 births in 2000 (p<0.001). Hypospadias was mild in 84% of cases, moderate-severe in 11% and unspecified in 5%, with the number of moderate-severe hypospadias almost doubling over time (p<0.01). There were 1465 (82%) cases of isolated hypospadias and 323 (18%) had co-existing anomalies. Infants with co-existing genital (relative risk (RR) 4.5; 95% CI: 3.3 to 6.1) or non-genital (RR 1.5; 95% CI: 1.0 to 2.2) anomalies were more likely to have moderate-severe hypospadias compared with isolated cases. CONCLUSION: Hypospadias affects one in 231 births and has been reported to have increased significantly over the last 20 years. Future investigation of the aetiology of hypospadias is important to identify potentially modifiable risk factors and ensure optimal male reproductive health in the future.     

Increasing prevalence of hypospadias in Western Australia, 1980-2000

Objectives

Hypospadias, a common birth defect, has shown widespread variation in reported rates and temporal trends across countries over the last 30 years. The aim of this study was to determine the prevalence and trends of hypospadias in an Australian population.

Design

Population‐based study of all male infants born in Western Australia (WA) between 1980 and 2000 diagnosed with hypospadias and notified to the WA Birth Defects Registry.

Main outcome measures

Prevalence of hypospadias, birth outcome and association with other congenital anomalies, stratified by degree‐of‐severity.

Results

1788 cases of hypospadias were registered in WA in 1980–2000 with an overall prevalence of 34.8 (95% confidence interval (CI): 33.2 to 36.4) cases per 10 000 births. The prevalence increased by 2.0% per annum (95% CI: 1.2% to 2.8%) from 27.9 in 1980 to 43.2 per 10 000 births in 2000 (p<0.001). Hypospadias was mild in 84% of cases, moderate‐severe in 11% and unspecified in 5%, with the number of moderate‐severe hypospadias almost doubling over time (p<0.01). There were 1465 (82%) cases of isolated hypospadias and 323 (18%) had co‐existing anomalies. Infants with co‐existing genital (relative risk (RR) 4.5; 95% CI: 3.3 to 6.1) or non‐genital (RR 1.5; 95% CI: 1.0 to 2.2) anomalies were more likely to have moderate‐severe hypospadias compared with isolated cases.

Conclusion

Hypospadias affects one in 231 births and has been reported to have increased significantly over the last 20 years. Future investigation of the aetiology of hypospadias is important to identify potentially modifiable risk factors and ensure optimal male reproductive health in the future.     

Decreasing incidence of burn injury in a rural state

OBJECTIVES: To determine changes in the incidence of burn injury since the regionalization of burn care and intensification of fire prevention initiatives that occurred in Maine during the 1970s. METHODS: Death certificate data from Maine and the United States for deaths due to fire or burns were obtained for 1960-98. Hospitalization and burn registry data were obtained for Maine from 1973-98. Frequencies and incidence rates were compared over time and, where possible, between Maine and the United States. RESULTS: During 1960-79, annual burn mortality in Maine averaged 5.1/100,000, with random variation. After this, the rate declined steadily to an average annual level of 1.4/100,000 during 1993-96. For the entire United States, average annual mortality declined from 4.2/100,000 during 1961-64 to 1.5/100,000 during 1993-96. Reduction in mortality has been principally due to prevention of dwelling fires. Hospitalization for burns in Maine was 34.8/100,000 during 1973-76 and declined to 10.6/100,000 during 1995-98. CONCLUSIONS: Burn prevention measures have dramatically reduced the incidence of death and hospitalization resulting from burns in Maine.     

Occupational injury deaths of 16 and 17 year olds in the US: trends and comparisons with older workers.

OBJECTIVE: To examine patterns of occupational injury deaths of 16 and 17 year olds in the United States for the three year period 1990-2, examine trends since the 1980s, and compare fatality rates with those of older workers. METHODS: Occupational injury deaths were analyzed using the death certificate based National Traumatic Occupational Fatalities (NTOF) surveillance system. Fatality rates were calculated using estimates of full time equivalent (FTE) workers based on data from the Current Population Survey, a monthly household survey. RESULTS: There were 111 deaths of 16 and 17 year olds for the years 1990-2. The average yearly rate was 3.5 deaths/100,000 FTE. The leading causes of death were motor vehicle related, homicide, and machinery related. All causes occupational injury fatality rates for 16 and 17 year olds were lower than for adults for 1990-2. Rates for the leading causes of death (motor vehicle related, homicide, and machinery related) were comparable or slightly higher than the rates for young and middle aged adult workers. Although rates decreased dramatically from 1980 to 1983, the decreasing trend attenuated in later years. CONCLUSIONS: Comparisons of youth fatality rates to those of adult workers should address differences in patterns of employment, most importantly hours of work. Comparisons to narrow age groupings of adults is preferable to a single category of all workers 18 years and older. Increasing compliance with federal child labor regulations could help reduce work related deaths of youth. Other measures are needed, however, as there are many work hazards, including those associated with homicides, that are not addressed by United States federal child labor law regulations.     

Resurgence of pertussis in Europe

BACKGROUND: A resurgence of pertussis has been observed in Canada, the United States and Australia since the 1980s, but inconsistent data are currently available for Europe. The objective of this paper is to describe the epidemiology of pertussis in Western European countries to discuss future vaccination strategies. METHODS: The European Community funded a network for the epidemiologic surveillance of measles and pertussis in 1998. Sixteen European countries provided national surveillance data for pertussis for the period 1998-2002 in a standard format. Data were pooled and analyzed to describe incidence rates by age group, seasonality, proportion of hospitalized patients and deaths among notified cases. RESULTS: Children younger than 1 year had the highest incidence during the entire period. Rates in the older than 14 years age group increased by 115% during the study period. Northern countries showed the highest incidence figures in all age groups. Among children younger than 1 year, 70% were admitted into hospital. Children younger than 6 months of age and those not vaccinated were most likely to be hospitalized. Thirty-two deaths were reported, 87% of which were in children younger than 6 months of age. CONCLUSIONS: Pertussis is far from being controlled in Europe. Whereas the incidence in children younger than 1 year was high but remained stable, rates in adults doubled in 5 years.     

Trends in BB/pellet gun injuries in children and teenagers in the United States, 1985–99

OBJECTIVE: To characterize national trends in non-fatal BB/pellet gun related injury rates for persons aged 19 years or younger in relation to trends in non-fatal and fatal firearm related injury rates and discuss these trends in light of injury prevention and violence prevention efforts. SETTING: The National Electronic Injury Surveillance System (NEISS) includes approximately 100 hospitals with at least six beds that provide emergency services. These hospitals comprise a stratified probability sample of all US hospitals with emergency departments. The National Vital Statistics System (NVSS) is a complete census of all death certificates filed by states and is compiled annually. METHODS: National data on BB/pellet gun related injuries and injury rates were examined along with fatal and non-fatal firearm related injuries and injury rates. Non-fatal injury data for all BB/pellet gun related injury cases from 1985 through 1999, and firearm related injury cases from 1993 through 1999 were obtained from hospital emergency department records using the NEISS. Firearm related deaths from 1985 through 1999 were obtained from the NVSS. RESULTS: BB/pellet gun related injury rates increased from age 3 years to a peak at age 13 years and declined thereafter. In contrast, firearm related injury and death rates increased gradually until age 13 and then increased sharply until age 18 years. For persons aged 19 years and younger, BB/pellet gun related injury rates increased from the late 1980s until the early 1990s and then declined until 1999; these injury rates per 100 000 population were 24.0 in 1988, 32.8 in 1992, and 18.3 in 1999. This trend was similar to those for fatal and non-fatal firearm related injury rates per 100 000 which were 4.5 in 1985, 7.8 in 1993, and 4.3 in 1999 (fatal) and 38.6 in 1993 and 16.3 in 1999 (non-fatal). In 1999, an estimated 14 313 (95% confidence interval (CI) 12 025 to 16 601) cases with non-fatal BB/pellet gun injuries and an estimated 12 748 (95% CI 7881-17 615) cases with non-fatal firearm related injuries among persons aged 19 years and younger were treated in US hospital emergency departments. CONCLUSIONS: BB/pellet gun related and firearm related injury rates show similar declines since the early 1990s. These declines coincide with a growing number of prevention efforts aimed at reducing injuries to children from unsupervised access to guns and from youth violence. Evaluations at the state and local level are needed to determine true associations.     

Intergenerational social mobility: the United States in comparative perspective

Emily Beller and Michael Hout examine trends in U.S. social mobility, especially as it relates to the degree to which a person's income or occupation depends on his or her parents' background and to the independent contribution of economic growth. They also compare U.S. social mobility with that in other countries. They conclude that slower economic growth since 1975 and the concentration of that growth among the wealthy have slowed the pace of U.S. social mobility. In measuring mobility, economists tend to look at income and sociologists, occupation. The consensus among those measuring occupational mobility is that the average correlation between the occupations of fathers and sons today ranges from 0.30 to 0.40, meaning that most variation in the ranking of occupations is independent of social origins. Those measuring income mobility tend to agree that the elasticity between fathers' and sons' earnings in the United States today is about 0.4, meaning that 40 percent of the difference in incomes between families in the parents' generation also shows up in differences in incomes in the sons' generation. Beller and Hout show that occupational mobility increased during the 1970s, compared with the 1940s-1960s, but there is some evidence to suggest that by the 1980s and 1990s it had declined to past levels. Existing data on income mobility show no clear trends over time, but increases in economic inequality during the 1980s made mobility more consequential by making economic differences between families persist for a longer time. In international comparisons, the United States occupies a middle ground in occupational mobility but ranks lower in income mobility. Researchers have used the variation in mobility to study whether aspects of a country's policy regime, such as the educational or social welfare systems, might be driving these results. There is as yet, however, no scholarly consensus about the sources of cross-national differences in mobility.     

Hospitalizations associated with rotavirus gastroenteritis in the United States, 1993-2002

BACKGROUND: In the United States, rotavirus gastroenteritis remains a common disease of children that results in many hospitalizations, clinic visits and medical costs. It is a common cause of morbidity and is associated with a high economic burden in developing countries. Prevention of hospitalizations is the primary target of rotavirus vaccines. METHODS: To update estimates of rotavirus hospitalization rates in the United States, we conducted a retrospective analysis of 10 years of national hospitalization data associated with gastroenteritis and used both direct and indirect methods to estimate the percentage of cases associated with rotavirus gastroenteritis. RESULTS: During 1993-2002, an average of 18% of all hospitalizations with gastroenteritis among children <5 years old were associated with rotavirus infection as determined by the rotavirus-specific International Classification of Diseases, 9th revision, Clinical Modification code. The annual proportion of rotavirus-associated hospitalizations increased from 15% in 1993-1995 to 21% in 2000-2002. Hospitalizations associated with rotavirus and those associated with nonspecific gastroenteritis had a marked winter-time seasonality and similar age distribution, which peaked among children between 3 and 24 months old. Using indirect estimation methods, 58,000 to 70,000 rotavirus-associated hospitalizations were estimated to occur each year in the United States. CONCLUSIONS: Rotavirus gastroenteritis remains an important cause of hospitalizations in the United States, and the rate has not declined from 1993 through 2002.     

Increase in deaths from pertussis among young infants in the United States in the 1990s

BACKGROUND: Severe pertussis primarily occurs among infants (<12 months of age). Despite high levels of immunization, reported pertussis cases increased in the United States in the 1990s among all age groups, including infants. METHODS: To characterize fatal pertussis cases, we analyzed pertussis deaths reported to CDC in the 1990s and compared these with data on pertussis deaths reported in the 1980s. Data from national surveillance systems and from available medical records were used, including data from analyses of deaths reported in 1992 through 1995. RESULTS: In 1980 through 1989, 77 pertussis deaths were reported; 61 deaths were among infants (1.67 deaths per million), including 49 among infants <4 months of age. In the 1990s 103 pertussis deaths were reported; 93 deaths were among infants (2.40 deaths per million), including 84 among infants <4 months of age. Of 89 infants with ethnicity data, 31 (36%) were Hispanic; the mortality rate among Hispanic infants (4.77 per million) was higher than among non-Hispanic infants (1.80 per million). Of 76 infants with reported gestational age, 40 (53%) were born at <37 weeks, including 22 (29%) who were born at <35 weeks. Severe pulmonary hypertension was a common lethal complication among infants. CONCLUSIONS: Pertussis deaths increased among infants too young to be protected by immunization. A disproportionate share of deaths were complicated by pulmonary hypertension and occurred among Hispanic infants and infants born at <37 weeks gestation. New approaches to prevent infection among infants <4 months of age and improved therapies for pertussis complications are needed.     

Adolescent occupational toxic exposures: a national study

BACKGROUND: While many previous studies describe workplace-associated injuries in adolescents, few focus on toxic exposures. Such incidents are unlikely to be reported to either federal or state agencies. However, poison control centers often get called about these poisonings and might serve as a resource for monitoring their occurrence. OBJECTIVE: To describe the frequency and severity of job-related toxic exposures involving adolescents, the specific toxic agents involved, and trends over time. METHODS: Occupational toxic exposures occurring in the United States between 1993 and 1997 were analyzed using the Toxic Exposure Surveillance System database compiled by the American Association of Poison Control Centers. Contingency tables with the chi(2) statistic were used to test bivariate associations. Logistic regression was performed to investigate trends over time. RESULTS: Of 301 228 workplace toxic exposures reported over 5 years, 8779 (3%) involved adolescents younger than 18 years. The most common agents involved were alkaline corrosives (13.2%), gases and fumes (12.0%), cleaning agents (9.7%), bleaches (8.3%), drugs (7.4%), acids (7.2%), and hydrocarbons (6.9%). The injuries were rated as severe in 14.2% of exposures, life-threatening in 0.3%, and there were 2 deaths. The proportionate frequency of occupational exposures occurring among adolescents vs adults increased over time (odds ratio, 1.003; P<.001). CONCLUSIONS: Adolescent occupational toxic exposures are an underrecognized hazard in the United States. Poison control center experience can be used to fill a gap in the surveillance of such injuries.     

Survival in infants with Down syndrome, Metropolitan Atlanta, 1979-1998

OBJECTIVE: Factors influencing survival among persons with Down syndrome (DS) are not well understood. We sought to evaluate survival of infants with DS and potential prognostic factors. STUDY DESIGN: Infants with DS who were born alive during 1979 to 1998 were identified using the Metropolitan Atlanta Congenital Defects Program (MACDP), a population-based surveillance system. To document vital status, we used data from hospital records, the National Death Index (NDI), and Georgia vital records. We estimated survival probability using the Kaplan-Meier product limit method and hazard ratios using a Cox proportional hazards model. RESULTS: Survival probability to 1 year was 92.9% (95% CI: 90.9-94.9) and to 10 years was 88.6% (95% CI: 85.0-92.2). Univariate analysis demonstrated that black maternal race, low birth weight, preterm birth, lower paternal education, presence of heart defects, and presence of other major congenital anomalies were important prognostic factors. After multivariate analysis, maternal race, presence of heart defects, low birth weight, and an interaction between maternal race and presence of heart defects were significantly associated with mortality risk. CONCLUSIONS: A racial disparity is apparent in survival for children with Down syndrome. Further study is needed to elucidate possible reasons for the racial disparity.     

A descriptive analysis of children's playground injuries in the United States 1990-4.

OBJECTIVES: To review playground injury statistics over a five year period in order to develop an awareness of how and where children in the United States are being injured. METHODS: All data are based on the United States Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) for playground related injuries during 1990-4. The surveillance data includes injuries recorded in more than 90 hospital emergency departments located throughout the United States. RESULTS: Each year there are roughly 211,000 preschool or elementary school-children in the United States who receive emergency department care for injuries associated with playground equipment. On average, 17 of these cases result in death. 70% of all injuries occur on public playgrounds, with nearly one third classified as severe. Swings, climbers, and slides are the pieces of playground equipment associated with 88% of all NEISS reported injuries. Falls to the surface are responsible for 70%. CONCLUSIONS: NEISS playground injury statistics contribute to our understanding of playground injuries. By identifying where and how children are injured, suggestions can be made in an attempt to make playgrounds safer.     

Disabilities and trends over time in a French county, 1980-91.

AIM: To describe trends over time and types of disability for children born in a French county from 1980 to 1991. METHODS: Data were collected from medical records of a morbidity register; disabled children with at least one severe deficiency have been included. Prevalence rates are given per 1000 resident children, over four three-year periods. RESULTS: Overall, 7.73 per 1000 children (that is, 1360 children), had a severe childhood disability, and the prevalence rate had increased significantly since 1980. This increase was mainly owing to an increase in cerebral palsy and psychiatric disorder prevalence rates. CONCLUSION: Future research aimed to explain these trends over time can be based on such data. The present knowledge is useful for planning purposes.     

Disabilities and trends over time in a French county, 1980-91

Aim: To describe trends over time and types of disability for children born in a French county from 1980 to 1991. Methods: Data were collected from medical records of a morbidity register; disabled children with at least one severe deficiency have been included. Prevalence rates are given per 1000 resident children, over four three-year periods. Results: Overall, 7.73 per 1000 children (that is, 1360 children), had a severe childhood disability, and the prevalence rate had increased significantly since 1980. This increase was mainly owing to an increase in cerebral palsy and psychiatric disorder prevalence rates. Conclusion: Future research aimed to explain these trends over time can be based on such data. The present knowledge is useful for planning purposes.     

A profile of mothers giving birth to infants with congenital rubella syndrome. An assessment of risk factors

To formulate strategies for elimination of congenital rubella syndrome, it is important to identify risk factors for delivering an infant affected by it. We analyzed cases of congenital rubella syndrome in infants born from 1970 to 1985 and reported to either one of two independent Centers for Disease Control surveillance systems. Mothers of infants with congenital rubella syndrome identified in both surveillance systems were disproportionately younger than mothers giving birth in the United States. The risk for delivering an infant with congenital rubella syndrome was approximately 2.5 times higher for blacks compared with whites for both reporting systems. A total of 18% of infants with congenital rubella syndrome born since 1979 were Hispanic (national population average, 7%). Both surveillance systems showed that, although primiparous mothers were at highest risk, 39% of women delivering infants affected by congenital rubella syndrome had had at least one previous live birth, suggesting that postpartum immunization could have prevented these congenital rubella syndrome cases. Young, black, and Hispanic primiparous women represent populations at elevated risk for delivering a congenital rubella syndrome-affected infant and should be specifically targeted for immunization.     

Youth,guns, and violent crime

Young people are overrepresented as both victims and perpetrators of violence. Indeed, some commentators have suggested that recent cohorts of youth have been composed of "superpredators" who have little regard for human life. The evidence, however, suggests that other factors are responsible for recent increases in youth gun violence. This article analyzes the extent and causes of youth violence in the United States, paying particular attention to the late 1980s and early 1990s, when rates of homicide and robbery committed by youth rose to extremely high levels. Examination of trends for these crimes shows that: The increase in violence in the United States during the late 1980s and early 1990s was due primarily to an increase in violent acts committed by people under age 20. Similarly, dramatic declines in homicide and robbery in recent years are attributable primarily to a decline in youth violence. The increase in youth homicide was predominantly due to a significant increase in the use of handguns, which converted ordinary teenage fights and other violent encounters into homicides. Several other interrelated factors also fueled the rise in youth violence, including the rise of illegal drug markets, particularly for crack cocaine, the recruitment of youth into those markets, and an increase in gun carrying among young people. The author points out that youth violence diminished as the crack markets shrank, law enforcement increased efforts to control youth access to guns, youth gun carrying declined, and the robust economy provided legitimate jobs for young people.     

前型尿道下裂患儿尿道口前移龟头成形术后尿道功能的评估

目的探讨尿道口前移龟头成形术（MAGPI）对前型尿道下裂患儿尿道功能的影响。方法2008年8月到2011年8月作者收治16例男性前型尿道下裂患儿,年龄2—10岁,平均4岁9个月,其中龟头型2例（12．5％）,冠状沟型14例（87．5％）;8例（50．0％）伴轻度阴茎下弯。依据Duckett报道的手术方法对16例患儿行MAGPI手术治疗。术前术后行尿流率检查。结果患儿均一次手术获成功。术后2～3个月尿流率检查提示最大尿流率、平均尿流率术前术后比较,均有统计学意义,最大尿流率由术前的（9．5±2．7）mL／s增加到术后（11．6±2．0）mL／s（P=0．022）;平均尿流率（6．2±1．6）mL／s增加到术后（7．7±1．4）mL／s（P=0．009）。结论MAGPI手术方法简单,成功率高,术后无尿道狭窄发生,患儿尿道功能较术前改善,对于合适的前型尿道下裂患儿是一种很好的手术方法。     

Classification of asthma severity in children: the contribution of pulmonary function testing

BACKGROUND: Despite increasing awareness of the National Asthma Education and Prevention Program guidelines, the relative contribution of symptom frequency or pulmonary function to the recommended asthma severity levels remains poorly understood. OBJECTIVE: To determine whether adding lung function measurements to clinical history substantially changes the asthma severity classification, thereby influencing treatment decisions. DESIGN: Baseline data were studied from children enrolled in 2 multicenter studies: phase 1 of the National Cooperative Inner-City Asthma Study (1992-1994) (cohort 1) and the Inner-City Asthma Study (1998-2001) (cohort 2). SETTING: Fifteen (8 for cohort 1 and 7 for cohort 2) major metropolitan inner-city areas in the United States. PARTICIPANTS: Inner-city children aged 8 through 11 years with asthma. MAIN OUTCOME MEASURES: Proportion of children reclassified from less severe asthma categories based on symptom frequency into more severe categories because of lung function. RESULTS: Of children with symptoms of mild intermittent asthma, 22.8% in cohort 1 and 27.7% in cohort 2 would be reclassified as having either moderate or severe persistent asthma. Of children with symptoms of mild persistent asthma, 31.2% in cohort 1 and 33.3% in cohort 2 would be similarly reclassified. CONCLUSIONS: In 2 different studies of inner-city children with asthma, approximately one third of the participants were reclassified into higher National Asthma Education and Prevention Program asthma severity categories when pulmonary function was considered in addition to symptom frequency. This may have direct implications for the undertreatment of asthma.