Longitudinal associations between asthma and general and abdominal weight status among Norwegian adolescents and young adults: the HUNT Study

BACKGROUND

In adolescents the temporal directionality to the asthma and adiposity association remains unclear. Asthma may be a consequence of obesity; however, asthma may increase adiposity.

OBJECTIVES

This study aimed to assess the associations between (i) baseline weight status and subsequent asthma and (ii) baseline asthma and subsequent weight status after 4 and 11 years of follow-up (N = 1543 and N = 1596, respectively) using data from three, sequentially enrolled population-based surveys of Norwegians aged 12-30 years from 1995 to 2008.

METHODS

Weight status was defined as general (body mass index) or abdominal (waist circumference) underweight, normal weight, overweight or obesity. Self-report physician-diagnosed asthma defined asthma status.

RESULTS

Over the longitudinal 11-year follow-up, baseline generally overweight or abdominally obese adolescents had increased risk of asthma. Likewise, baseline asthmatics had increased risk of general overweight or abdominal obesity. After sex stratification, these associations were stronger in males. Generally (odds ratio [OR] 1.90; 95% confidence interval [CI] 1.32, 2.73) or abdominally (OR 1.66; 95% CI 1.13, 2.44) overweight males were at increased risk of asthma. Baseline asthmatic males were also at increased risk of general (OR 2.14; 95% CI 1.54, 2.98) and abdominal (OR 1.77; 95% CI 1.27, 2.47) overweight.

CONCLUSIONS

Among Norwegian adolescents, a bidirectional association of asthma and adiposity was observed in males. Each baseline condition increased the risk of the other condition over time. No association was observed in females.

Continuous infusion versus intermittent bolus doses of indomethacin for patent ductus arteriosus closure in symptomatic preterm infants

BACKGROUND

Indomethacin is a prostaglandin inhibitor used for the prevention and the treatment of patent ductus arteriosus (PDA). Although a 3-dose schedule has been commonly used, there is no consensus on optimal dosage and duration of indomethacin therapy for PDA closure. There are potential adverse effects of indomethacin use in premature infants such as a reduction in cerebral, mesenteric and renal blood flow and platelet dysfunction. Administering indomethacin continuously over 36-hours has been suggested as a safer and more effective option to prevent such adverse effects.

OBJECTIVES

To compare the efficacy and safety of continuous infusion versus bolus administration of indomethacin in closing a symptomatic PDA in preterm infants.

SEARCH STRATEGY

The standard search strategy of Cochrane Neonatal Review was used: MEDLINE and EMBASE (1966 - March 2007), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2007), bibliographies of reviews and trials were examined for references to other trials, previous symposia proceedings published in Pediatric Research (Pediatric Academic Societies Annual Meeting Abstract Book, 1972 - 2006). No language restrictions were applied.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing continuous indomethacin infusion to bolus doses for closure of a symptomatic PDA in preterm infants with a symptomatic PDA diagnosed clinically and/or by echocardiography.

DATA COLLECTION AND ANALYSIS

The methodological quality of each study was assessed. Authors were contacted regarding missing data as well as to inquire about the outcomes that were not reported. Meta-analysis was performed to calculate relative risk (RR), risk difference (RD) and 95% confidence intervals (CI).

MAIN RESULTS

Only two small trials comparing continuous versus bolus indomethacin were eligible. Analysis of these studies showed that, although the primary outcome of PDA closure on days two and five slightly favored bolus administration, there was no statistical difference between the two groups. The estimates for PDA closure were RR 1.57 (95% CI 0.54, 4.60), RD 0.10 (95% CI -0.13, 0.33) for day 2 and RR 2.77 (95% CI 0.33, 23.14), RD 0.15 (95% CI -0.13, 0.42) for day five. There was no statistical difference between the bolus and continuous groups for the secondary outcomes of reopening of PDA, neonatal mortality, intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). These analyses were based on a very small number of events reported by these trials. None of the trials reported on outcomes such as requirement for retreatment with indomethacin or surgical ligation, mortality, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP), neurodevelopmental outcome and isolated intestinal perforation. The review demonstrated that there was a decrease in cerebral blood flow velocity after bolus injections and that the difference between the bolus and continuous infusion groups remained significant for 12 - 24 hour. In one study (Christmann 2002), the decrease in blood flow was maximum at 10 minutes [MD -46.40 (95% CI -75.41, -17.39)], while the other study (Hammerman 1995) reported a maximum drop at 30 minutes [MD -55.60 (95% CI -62.92, -48.28)]. Similar decrease in blood flow to the renal and mesenteric circulations following bolus administration was reported in one study (Christmann 2002). In both of these circulations, the decrease was maximum 30 minutes after the bolus injection [typical estimates for renal and mesenteric circulations, respectively: MD -42.00 (95% CI -76.59, -7.41) and MD -26.50 (95% CI -45.34, -7.66)] and lasted about two hours. None of the trials detected predefined levels of decreased urine output and increased levels of BUN and creatinine.

AUTHORS' CONCLUSIONS

Due to a paucity of events and lack of precision, the available data was found to be insufficient to draw conclusions regarding the efficacy of continuous indomethacin infusion versus bolus injections for the treatment of PDA. Although continuous indomethacin seems to cause less alterations in cerebral, renal and mesenteric circulations, the clinical meaning of this effect is unclear. Definitive recommendations about the preferred method of indomethacin administration i.e. continuous versus bolus infusions for the treatment of PDA in premature infants cannot be made based on the current findings of this review.

A systematic review: antipsychotic augmentation with treatment refractory obsessive-compulsive disorder

As many as half of obsessive-compulsive disorder (OCD) patients treated with an adequate trial of serotonin reuptake inhibitors (SRIs) fail to fully respond to treatment and continue to exhibit significant symptoms. Many studies have assessed the effectiveness of antipsychotic augmentation in SRI-refractory OCD. In this systematic review, we evaluate the efficacy of antipsychotic augmentation in treatment-refractory OCD. The electronic databases of PubMed, PsychINFO (1967-2005), Embase (1974-2000) and the Cochrane Central Register of Controlled Trials (CENTRAL, as of 2005, Issue 3) were searched for relevant double-blind trials using keywords 'antipsychotic agents' or 'neuroleptics' and 'obsessive-compulsive disorder'. Search results and analysis were limited to double-blind, randomized control trials involving the adult population. The proportion of subjects designated as treatment responders was defined by a greater than 35% reduction in Yale Brown Obsessive-Compulsive Scale (Y-BOCS) rating during the course of augmentation therapy. Nine studies involving 278 participants were included in the analysis. The meta-analysis of these studies demonstrated a significant absolute risk difference (ARD) in favor of antipsychotic augmentation of 0.22 (95% confidence interval (CI): 0.13, 0.31). The subgroup of OCD patients with comorbid tics have a particularly beneficial response to this intervention, ARD=0.43 (95% CI: 0.19, 0.68). There was also evidence suggesting OCD patients should be treated with at least 3 months of maximal-tolerated therapy of an SRI before initiating antipsychotic augmentation owing to the high rate of treatment response to continued SRI monotherapy (25.6%). Antipsychotic augmentation in SRI-refractory OCD is indicated in patients who have been treated for at least 3 months of maximal-tolerated therapy of an SRI. Unfortunately, only one-third of treatment-refractory OCD patients show a meaningful treatment response to antipsychotic augmentation. There is sufficient evidence in the published literature, demonstrating the efficacy of haloperidol and risperidone, and evidence regarding the efficacy of quetiapine and olanzapine is inconclusive. Patients with comorbid tics are likely to have a differential benefit to antipsychotic augmentation.

The influence of air conditioning, humidity, temperature and other household characteristics on mite allergen concentrations in the northeastern United States

BACKGROUND

Information about the influence of housing and occupant characteristics on mite allergen concentrations is crucial to determine which methods could be used to decrease exposure of susceptible subjects.

OBJECTIVES

To identify housing and occupant characteristics that are associated with mite allergen concentrations in house dust collected from living rooms and mattresses.

METHODS

We collected dust samples from 750 homes in the northeastern US. The influence of various characteristics on concentrations of mite allergens (Der p 1 and Der f 1) was studied using multiple linear regression analysis.

RESULTS

Some characteristics, like absence of air conditioners, the presence of mold or mildew, and a lower temperature were consistently associated with higher concentrations of both mite allergens in dust from all sampling locations. However, none of these factors changed Der p 1 or Der f 1 concentrations by more than a factor of 2. People of white ethnic background had roughly two times higher mite allergen concentrations, while family income, family size, and education level only marginally influenced mite allergen concentrations.

CONCLUSIONS

Various housing characteristics have some influence on mite allergen concentrations, and could possibly be used to decrease exposure of susceptible subjects. However, only a limited percentage of the variation in mite allergen concentrations was explained by these characteristics.

Steroids for acute spinal cord injury

BACKGROUND

Acute spinal cord injury is a devastating condition typically affecting young people with a preponderance being male. Steroid treatment in the early hours of the injury is aimed at reducing the extent of permanent paralysis during the rest of the patient's life.

OBJECTIVES

To review randomized trials of steroids for acute spinal cord injury.

SEARCH STRATEGY

The review draws on the search strategy developed by the Cochrane Injuries Group. In addition, files of the National Acute Spinal Cord Injury Study have been reviewed and a Medline search conducted.

SELECTION CRITERIA

All published or unpublished randomized controlled trials of steroid treatment for acute spinal cord injury in any language.

DATA COLLECTION AND ANALYSIS

Data have been abstracted from original trial reports. For the NASCIS, Japanese and French trials, additional data (e.g. SDs) have been obtained from the original authors.

MAIN RESULTS

There are few trials in this area of medical care. Only one steroid has been extensively studied, methylprednisolone sodium succinate, which has been shown to improve neurologic outcome up to one year post injury if administered within eight hours of injury and in a dose regimen of: bolus 30mg/kg administered over 15 minutes with a maintenance infusion of 5.4 mg/kg per hour infused for 23 hours. The initial North American trial was replicated in a Japanese trial but not in the one from France. Data has been obtained from the latter studies to permit appropriate meta-analysis of all three trials. This analysis indicates significant recovery in motor function after methylprednisolone therapy when administration commences within eight hours of injury. A more recent trial indicates that if methylprednisolone therapy is given for an additional 24 hours (for a total of 48 hours), additional improvement in motor neurologic function and functional status is observed. This is particularly observed if treatment cannot be started until between three to eight hours after injury. The same methylprednisolone therapy has been found effective in whiplash injuries and a modified regimen found to improve recovery after surgery for lumbar disc disease.

REVIEWER'S CONCLUSIONS

High dose methylprednisolone steroid therapy is the only pharmacological therapy shown to have efficacy in a Phase Three randomized trial when it can be administered within eight hours of injury. A recent trial indicates additional benefit by extending the maintenance dose from 24 to 48 hours if start of treatment must be delayed to between three and eight hours after injury. There is an urgent need for more randomized trials of pharmacological therapy for acute spinal cord injury.

Methylprednisolone and acute spinal cord injury: an update of the randomized evidence

OBJECTIVES

Randomized trials are widely recognized as providing the most reliable evidence for assessing efficacy and safety of therapeutic interventions. This evidence base is used to evaluate the current status of methylprednisolone (MPSS) in the early treatment of acute spinal cord injury.

METHODS

Medline, CINAHL, and other specified databases were searched for MeSH headings "methylprednisolone and acute spinal cord injury." The Cochrane Library and an existing systematic review on the topic were also searched.

RESULTS

Five randomized controlled trials were identified that evaluated high-dose MPSS for acute spinal cord injury. Three trials by the NASCIS group were of high methodologic quality, and a Japanese and French trial of moderate to low, methodologic quality. Meta-analysis of the final result of three trials comparing 24-hour high-dose MPSS with placebo or no therapy indicates an average unilateral 4.1 motor function score improvement (95% confidence interval 0.6-7.6, P = 0.02) in patients treated with MPSS. This neurologic recovery is likely to be correlated with improved functional recovery in some patients. The safety of this regimen of MPSS is evident from the spinal cord injury trials and a systematic review of 51 surgical trials of high-dose MPSS.

CONCLUSION

High-dose MPSS given within 8 hours of acute spinal cord injury is a safe and modestly effective therapy that may result in important clinical recovery for some patients. Further trials are needed to identify superior pharmacologic therapies and to test drugs that may sequentially influence the postinjury cascade.

Use of health services by insurance status among children with asthma

OBJECTIVES

It is well known that asthmatic children receiving Medicaid use the emergency department (ED) more frequently than otherwise-insured asthmatic children. However, the extent to which this difference is attributable to provider characteristics, medication use, access to primary care, and symptomatology is poorly understood. These factors were explored as independent predictors of health care utilization.

METHODS

Baseline data from a prospective cohort study of childhood asthma severity were used. Subjects were recruited from seven New England hospitals. Home interviews collected data on monthly symptoms, health care visits, insurance status, as well as sociodemographics and asthma-related risk factors (n = 804). Characteristics of providers' practices, board certifications, and asthma specialty were obtained from Folio's Medical Dictionaries for Connecticut and Massachusetts.

RESULTS

After adjusting for frequency of asthma-related primary care visits, primary provider practice type, use of asthma specialist, age, gender, medication use, and symptomatology, Medicaid children still used the ED more frequently for asthma services than privately insured children (RR, 1.7; 95% CI, 1.1, 2.5). In general, race/ethnicity did not modify the relationship between insurance status and health care use, except that black children receiving Medicaid were 90% (95% CI, 0.0, 0.7) less likely to have had > or = 3 routine primary care visits for asthma in the previous year than black privately insured children. White children receiving Medicaid were 2.5 (95% CI, 1.0, 6.9) times more likely to use the ED for asthma than privately insured white children.

CONCLUSIONS

The results suggest that enabling, structural, and need factors do not necessarily explain observed differences in pediatric asthma health care use by insurance status. Future investigation must explore other explanatory factors such as maternal attitudes and beliefs and patient-provider communication.

Maternal caffeine intake and intrauterine growth retardation

This study estimates the effect of maternal caffeine consumption throughout pregnancy on fetal growth. We studied 2,714 women who delivered a liveborn infant between 1988 and 1991. Detailed information regarding coffee, tea, and soda drinking during the first and third trimesters of pregnancy was obtained. Average caffeine intake during month 1 of pregnancy was higher than for month 7 (72.4 vs 54.0 mg per day). Consumption of >300 mg caffeine per day during month 1 (adjusted odds ratio = 0.91; 95% confidence interval = 0.44--1.90) and during month 7 (adjusted odds ratio = 1.00; 95% confidence interval = 0.37--2.70) was not associated with intrauterine growth retardation. There was little evidence for any effect modification due to cigarette smoking on the caffeine associations. This study provides evidence that antenatal caffeine consumption has no adverse effect on fetal growth.

The relation between fungal propagules in indoor air and home characteristics

BACKGROUND

Questionnaires are commonly used in epidemiologic studies to obtain information about house characteristics in order to predict the household aeroallergen exposure levels. However, the reliability of the predictions made with the questionnaires has not been evaluated. To address this issue, we compared objectively measured fungal propagules including the most frequently isolated mold genera (i.e., Alternaria, Aspergillus, Cladosporium, Penicillium, etc.) in a large sample of homes and compared these measured values to the questionnaire-determined household characteristics.

METHODS

As part of a prospective cohort study on the relation between residential allergen exposure and development of asthma in neonates, fungal air samples were collected from infant bedrooms and main living areas in 1000 homes in the Northeast USA, from December 1996 to January 1999. A Burkard portable air sampler was used in combination with DG-18 and MEA agars. A questionnaire was used to obtain information on host and house characteristics that may have an impact on the presence of fungal propagules in the air. This included information on observation of moisture problems (e.g., water leakage or damage, and mold or mildew growth), ventilation and heating facilities, building age and type, number of occupants, annual household income, presence of pets and pests, cleaning regimens, etc.

RESULTS

The number of CFU/m3 air collected on MEA was significantly higher than on DG-18 (means, respectively, 1033.5 and 846.0 CFU/m3) (P < 0.0005). However, there was no significant difference between the numbers of CFU/m3 air collected from the main living area and from the infant bedroom. There was only a very weak relationship between the house characteristics, as described by questionnaire, and the presence of fungal propagules in indoor air. Only the temperature, relative humidity, season, and cats inside homes had a statistically significant impact on the presence of fungal propagules in indoor air.

CONCLUSION

The presence of fungal propagules in indoor air cannot be reliably predicted by home characteristics. Actual measurements are required for fungal exposure assessment, and the use of only one medium to collect samples in one location in a home might be adequate to represent residential levels of fungi in indoor air.

A childhood asthma severity scale: symptoms, medications, and health care visits

BACKGROUND

Although there are current measures to evaluate childhood asthma severity for clinical diagnosis and treatment, there is no standard valid measure to evaluate childhood asthma severity for large-scale epidemiologic studies.

OBJECTIVES

To develop and test a childhood asthma severity scale (CHAS) for clinimetric validity and to determine differences in symptoms, medication use, and health care visits by participant characteristics.

METHODS

Eight hundred ninety-seven actively asthmatic children under the age of 12 years were selected from a general population of children. Children were selected from a screening questionnaire administered at six Connecticut hospitals that serve large minority populations in Bridgeport, New Haven, Hartford, and Danbury and one hospital serving south central Massachusetts. Twelve-month baseline data for a prospective cohort study of childhood asthma severity were collected on a monthly basis through home interviews. Home interviews addressed questions on daily symptoms, medication use, and health care visits. A severity scale was constructed using three dimensions: symptoms, medication use, and health care visits.

RESULTS

CHAS has sufficient preliminary content, construct, and predictive validity. Despite similarities in symptoms, there were health care utilization and medication differentials according to race and ethnicity, insurance status, family income, and maternal education.

CONCLUSIONS

CHAS is a potentially useful measure of asthma severity for large-scale epidemiologic studies. It seems that CHAS has sufficient clinimetric properties.

Intergenerational effects of high socioeconomic status on low birthweight and preterm birth in African Americans

As socioeconomic status (SES) increases, the incidence of low birthweight and preterm birth decreases irrespective of social class. However, low birthweight remains twice as high for African-American women as for white women even when SES is controlled. This study examines to what extent second generation high SES African-American women experience improvement in birthweight and gestational age. One hundred eighty-nine former Meharry students were surveyed. Identified were 934 births that are the children and grandchildren of these students who matriculated at Meharry. These infants are compared with a cohort of white mothers from a study in the School of Public Health at Yale University. Low birthweight was reduced in the third generation high SES African-American children (6.9%) from the second generation (11.4%) but remained higher than white children (3.3%). Results showed that African-American third generation children remained at higher risk for low birthweight than were white children (relative risk [RR], 1.78; 95% confidence interval [CI], 1.03, 3.09). Similar results were observed for preterm delivery where the increased risk to third generation African-American children was 3.16 (1.89, 5.27). Persistent strong ethnic differences in birthweight in this high SES cohort (OR = 3.16, 95% CI, 1.89-5.27) support a conclusion that African-American women have birthweight distributions that are somewhat lighter than white women. This may explain a portion of current ethnic differences in birthweight. It is also possible that persistent psychosocial and behavioral factors continue to negatively influence birthweight, even in second generation high SES African-American mothers. This explanation will require identification of powerful risk factors, which are largely unrelated to those presently under investigation.

Clinical measurement, statistical analysis, and risk-benefit: controversies from trials of spinal injury

BACKGROUND

The National Acute Spinal Cord Injury Studies have been a series of trials assessing the role of pharmacologic agents in the prevention of secondary neuronal damage after acute spinal cord injury.

METHODS

The trials were multicenter randomized, controlled studies.

RESULTS

Two trials have demonstrated the efficacy of high-dose methylprednisolone in improving neurologic and functional recovery and have shown a reassuring safety profile.

CONCLUSION

This study responds to a recent commentary on these trials and examines in particular the roles of clinical measurement, statistical analysis, and risk benefit in assembling evidence for or against innovative therapies.

A systematic review and meta-analysis of prospective studies on the association between maternal cigarette smoking and preterm delivery

We have attempted to quantify the most up-to-date estimate of the association between cigarette smoking by the mother and preterm delivery. Studies were selected for inclusion in this review if they were prospective, reported data stratified across at least two levels of maternal smoking, and defined preterm delivery on the basis of gestational age. In a meta-analysis we combined results from multiple studies that reported on preterm delivery and maternal smoking during pregnancy. Pooled odds ratios were computed for various strata of smoking intensity with the Mantel-Haenszel fixed-effects model. Twenty studies met all inclusion criteria and were included in meta-analysis. The pooled point estimate from 20 prospective studies on any maternal smoking versus no maternal smoking was 1.27 (95% confidence interval, 1.21-1.33). Subgroup analyses stratifying maternal smoking on number of cigarettes per day suggest a dose-response relationship at low to moderate levels of smoking, which was not further increased at high levels of smoking. A nonsignificant level of publication bias appears to exist in the smoking-preterm delivery literature. Cigarette smoking is a preventable risk factor that is associated with preterm delivery. Consistent results across many study populations and research designs and evidence of a dose-response relationship support its causal role in preterm delivery.

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.

Magnetic resonance imaging and neurological recovery in acute spinal cord injury: observations from the National Acute Spinal Cord Injury Study 3

STUDY DESIGN

Data are from a multicenter, randomized, double blind clinical trial of acute spinal cord injury.

OBJECTIVES

To evaluate the prognostic value of magnetic resonance imaging (MRI) for randomized patients in the National Acute Spinal Cord Injury Study 3 (NASCIS).

SETTING

Sixteen spinal cord injury centers throughout the United States and Canada.

METHODS

Of 499 patients randomized in NASCIS 3 between December 1991 and September 1995, MRI was electively done on 191 patients within 72 h of injury. Indications of hemorrhage, edema, and contusion were recorded by standard protocol. Neurological impairment as determined by motor function, response to pin prick and light touch was assessed at admission to the participating center and 6 weeks after injury. Change in neurological function was obtained by subtracting the score of each neurological parameter at admission from that measured at 6 weeks. Spinal cord surgery performed within the 3 days after injury was noted. Data were analyzed by: chi square, analysis of variance, multiple logistic regression and linear regression models.

RESULTS

Patients with hemorrhage were much more likely to have a complete injury (OR=2.88, 95 Cl 1.32, 6.23); however this association was much reduced when the initial neurological examination was taken into account (AOR=1.43, 95% Cl 0.55, 3.73) and was no longer a significant predictor of injury. MRI evidence of cord edema was the strongest predictor of reduced improvement in motor function (-3.34 points, P=0.06) and light touch sensation (-3.41 points, P=0.05) at 6 weeks.

CONCLUSIONS

Cord hemorrhage, contusion, and edema on MRI were not associated with diagnosis of a complete cord injury after neurological assessment from the initial clinical examination was taken into account. Prediction of a worse 6 week neurological status was weakly associated with the presence of edema diagnosed by MRI. As MRI technology improves, these diagnostic and predictive capabilities need to be re-assessed.

SPONSORSHIP

NASCIS 3 was funded by the National Institute of Neurological Disorders and Stroke at the National Institutes of Health, Washington, DC, USA. Pharmacia and Upjohn provided study drugs and placebos; they also monitored data quality, and funded additional tests, in accordance with Food and Drug Administration regulatory requirements. Dr Bracken has served as an occasional paid consultant to Pharmacia and Upjohn.

Environmental tobacco smoke exposure and small-for-gestational-age birth

The aim of this analysis was to examine the effect of environmental tobacco smoke exposure on the risk of small-for-gestational-age (SGA) birth. The study population included 2,283 nonsmokers from a nested cohort study undertaken in southern Connecticut from 1988 to 1992. The duration and intensity of exposures incurred at multiple locations during the third trimester of pregnancy were measured by postpartum interview. The effect of exposure on birth weight and on incidence of SGA birth was assessed by multivariate logistic and linear regression. An estimated 26.5% of the women had been exposed to environmental tobacco smoke for at least 1 hour per week during the third trimester. The median duration of exposure among the exposed over all locations was 5 hours per week. The adjusted odds ratio for SGA birth in exposed mothers compared with unexposed mothers, using a dichotomous exposure variable, was 0.82 (95% confidence interval: 0.51, 1.33). The adjusted birth weight difference associated with exposure was -1.2 g (95% confidence interval: -43.3, 41.0). No effect of environmental tobacco smoke exposure on fetal growth was seen in this relatively homogeneous upper middle class group of women exposed at low levels. This is reassuring for women exposed at low levels, but it does not exclude the possibility of an effect in women exposed to higher levels of environmental tobacco smoke.

Healthy women's PEF variations with ambient summer concentrations of PM10, PM2.5, SO42-, H+, and O3

The relationship between ambient air pollution and daily change in peak expiratory flow (PEF) was studied in a sample of 473 nonsmoking women (age 19 to 43 yr) in Virginia over summers 1995- 1996. Daily 24-h averages of particulate matter (PM2.5 and PM10), fine particulate sulfate (SO42-) and strong acid (H+), hourly ozone (O3), and select meteorologic variables (e.g., temperature) were collected at a regional outdoor monitoring site. Subjects took PEF measurements twice daily for a 2-wk period using a standard MiniWright peak flow meter. Concurrent measures for summer periods of 24-h PM2.5 (micrograms/m3) ranged from 3.5 to 59.7; H+ (nmol/m3) from 0 to 250; maximal daily 8-h average O3 (ppb) from 17.0 to 87.6. Morning PEF decrements were significantly associated with H+ and PM2. 5. An increase of 50 etamol/m3 of H+ and 10 micrograms/m3 of PM2.5 related to decreases of 0.89 (95% CI = 0.21 to 1.57) and 0.73 (95% CI = 0.07 to 1.38) L/min in morning PEF, respectively. Ozone was the only exposure related to evening PEF with 5-d cumulative lag exposure showing the greatest effect; 7.65 L/ min (95% CI = 2.25 to 13.0) decrease per 30 ppb O3 increase. Separate physiologic effects were observed for summer ambient concentrations of two different pollutants (PEF decrements related to PM2.5 in morning and O3 in evening) at concentrations below the new U.S. EPA 24-h ambient air quality standard for PM2.5 and 8-h standard for O3.

Methodological issues in the study of rare exposures and rare outcomes in perinatal epidemiology

Epidemiologic study of rare exposures and rare outcomes is complicated. For perinatal epidemiology, a prospective cohort study design is preferred for reproductive outcomes with incidences of at least 5%. Case-control studies are generally used to investigate rare outcomes with incidences from 5 per 1000 to less than 1 per 1000. However, obtaining data on large numbers of rare cases can be difficult. The use of nested case-control designs or nested prospective studies may be particularly useful in perinatal epidemiology.

Interpregnancy interval and disparity in term small for gestational age births between black and white women

OBJECTIVE

To examine the influence of interpregnancy interval on the elevated risk of term small for gestational age (SGA) births to black women.

METHODS

This study is a secondary analysis of data from the Delivery Interview Program, a hospital-based cohort study of 12,718 women conducted at the Boston Hospital for Women from 1977 to 1980. The current analysis was limited to black and white parous women who gave birth to term infants during the study and whose last previous pregnancies had also resulted in term, live births. There were 578 black and 3400 white women who met these criteria. The rates of term SGA births for black and white women were calculated according to six interpregnancy intervals (6 or less, 6-12, 12-24, 24-36, 36-60, or longer than 60 months). Multiple logistic regression was used to control for confounding.

RESULTS

The overall rate of term SGA births was 6.4% for black women compared with 3.9% for white women (relative risk [RR] 1.7, 95% confidence interval [CI] 1.2, 2.4). Black women were also more likely than white women to have interpregnancy intervals of 6 months or less (9.2% black, 4.8% white; RR 1.9, 95% CI 1.4, 2.6). At every interpregnancy interval, black women had a higher rate of term SGA births than white women. After controlling for interpregnancy interval in a logistic regression analysis, the increased risk of SGA delivery among black women remained unchanged (odds ratio 1.7, 95% CI 1.1, 2.5).

CONCLUSION

Although black women were more likely than white women to have SGA births and short interpregnancy intervals, differences in interpregnancy intervals between the races did not explain the disparity in term SGA births.

Methylprednisolone or tirilazad mesylate administration after acute spinal cord injury: 1-year follow up. Results of the third National Acute Spinal Cord Injury randomized controlled trial

OBJECT

A randomized double-blind clinical trial was conducted to compare neurological and functional recovery and morbidity and mortality rates 1 year after acute spinal cord injury in patients who had received a standard 24-hour methylprednisolone regimen (24MP) with those in whom an identical MP regimen had been delivered for 48 hours (48MP) or those who had received a 48-hour tirilazad mesylate (48TM) regimen.

METHODS

Patients for whom treatment was initiated within 3 hours of injury showed equal neurological and functional recovery in all three treatment groups. Patients for whom treatment was delayed more than 3 hours experienced diminished motor function recovery in the 24MP group, but those in the 48MP group showed greater 1-year motor recovery (recovery scores of 13.7 and 19, respectively, p=0.053). A greater percentage of patients improving three or more neurological grades was also observed in the 48MP group (p=0.073). In general, patients treated with 48TM recovered equally when compared with those who received 24MP treatments. A corresponding recovery in self care and sphincter control was seen but was not statistically significant. Mortality and morbidity rates at 1 year were similar in all groups.

CONCLUSIONS

For patients in whom MP therapy is initiated within 3 hours of injury, 24-hour maintenance is appropriate. Patients starting therapy 3 to 8 hours after injury should be maintained on the regimen for 48 hours unless there are complicating medical factors.

Maternal anthropometric factors and risk of primary cesarean delivery

OBJECTIVES

This study examined absolute and proportional gestational weight gain and prepregnancy body mass index as predictors of primary cesarean delivery.

METHODS

Data were derived from a prospective study of pregnancy outcome risk factors in 2301 women in greater New Haven, Conn, who had singleton deliveries by primary cesarean (n = 312) or vaginal delivery (n = 1989) and for whom height, prepregnancy weight, and weight gain were available. Women were divided into 4 body mass index groups (underweight, low average, high average, and obese) and further subdivided into 8 groups according to median proportional or absolute weight gain.

RESULTS

Risk of cesarean delivery increased with increasing body mass index and gestational weight gain greater than the median for one's body mass index. Proportional weight gain was more predictive of cesarean delivery than absolute weight gain. Underweight women gaining more than 27.8% of their prepregnancy weight had a 2-fold adjusted relative risk of cesarean delivery.

CONCLUSIONS

Proportional weight gain is an important predictor of cesarean delivery for underweight women; high body mass index is also predictive of increased risk.

Correlates of residential wiring code used in studies of health effects of residential electromagnetic fields

The home wiring code is the most widely used metric for studies of residential electromagnetic field (EMF) exposure and health effects. Despite the fact that wiring code often shows stronger correlations with disease outcome than more direct EMF home assessments, little is known about potential confounders of the wiring code association. In a study carried out in southern Connecticut in 1988-1991, the authors used strict and widely used criteria to assess the wiring codes of 3,259 homes in which respondents lived. They also collected other home characteristics from the tax assessor's office, estimated traffic density around the home from state data, and interviewed each subject (2,967 mothers of reproductive age) for personal characteristics. Women who lived in very high current configuration wiring coded homes were more likely to be in manual jobs and their homes were older (built before 1949, odds ratio (OR) = 73.24, 95% confidence interval (CI) 29.53-181.65) and had lower assessed value and higher traffic densities (highest density quartile, OR = 3.99, 95% CI 1.17-13.62). Because some of these variables have themselves been associated with health outcomes, the possibility of confounding of the wiring code associations must be rigorously evaluated in future EMF research.

Alarums false, alarums real: challenges and threats to the future of epidemiology

PURPOSE

A review of recent threats and challenges to epidemiology suggests that some represent an opportunity to advance the discipline while others are a major threat to conducting epidemiologic work.

METHODS

Two issues are identified which should advance the publication and conduct of epidemiologic research. Three are discussed that exemplify current threats.

RESULTS

Epidemiologists have a role in helping journalists improve the communication of risk information in the media. Methodological advances for studies of rare exposure being related to rare disease should reduce the frequency of conflicting results in the epidemiologic literature. Three significant external forces that threaten epidemiologic research are identified. These are: unbridled discovery during litigation as exemplified by Bendectin, breast implants and cellular telephones; over zealous privacy laws; and the negative impact of managed care on epidemiologic research.

CONCLUSIONS

The American College of Epidemiology has a major role to play in protecting the profession from some of the real threats that face it, and in helping meet the challenges.

Spontaneous abortion and exposure to electric blankets and heated water beds

We conducted a prospective study (N = 2,967) to evaluate the relation of spontaneous abortion with use of electrically heated beds (electric blankets and heated water beds) during pregnancy. At interview, 61.5% of women were at less than 12 weeks gestation, and 38.5% were between 13 and 16 weeks; thus, very early pregnancy losses would have been excluded. Information regarding exposure to electric beds was obtained for the month of conception and the 7 days before interview. Electric blanket use at conception was associated with an increased risk of spontaneous abortion in the unadjusted analysis [relative risk (RR) = 1.84; 95% confidence interval (CI) = 1.08-3.13], but adjustment for other factors reduced the risk slightly [odds ratio (OR) = 1.74; 95% CI = 0.96-3.15]. Heated water bed use was not associated with an increased risk of spontaneous abortion at conception (OR = 0.59; 95% CI = 0.33-1.07) or at interview (OR = 0.63; 95% CI = 0.36-1.12). Measures of dose response (daily use, hours of use, or temperature setting) were not associated with increased risk. Wire code data were obtained for the first, or only, house lived in during pregnancy. Women living in homes classified as "very high" or "ordinary high" current configuration were not at greater risk than women living in homes with buried wires. Nor was there any trend for increased risk of spontaneous abortion by wire code category. This study does not support the hypothesis that use of electric beds or residence in a high current configuration home increases the risk of spontaneous abortion; however, it indicates that electric blanket use at the time of conception and in early pregnancy may be associated with a slight increase in risk of pregnancy loss.

Low-to-moderate gestational alcohol use and intrauterine growth retardation, low birthweight, and preterm delivery

PURPOSE

Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy.

METHODS

This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988-1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birthweight.

RESULTS

Mild drinking, defined as > 0.10-0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20-0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64-5.05) for light drinking and 2.96 (95% CI, 1.32-6.67) for mild-to-moderate alcohol consumption.

CONCLUSIONS

Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study

OBJECTIVE

To compare the efficacy of methylprednisolone administered for 24 hours with methyprednisolone administered for 48 hours or tirilazad mesylate administered for 48 hours in patients with acute spinal cord injury.

DESIGN

Double-blind, randomized clinical trial.

SETTING

Sixteen acute spinal cord injury centers in North America.

PATIENTS

A total of 499 patients with acute spinal cord injury diagnosed in National Acute Spinal Cord Injury Study (NASCIS) centers within 8 hours of injury.

INTERVENTION

All patients received an intravenous bolus of methylprednisolone (30 mg/kg) before randomization. Patients in the 24-hour regimen group (n=166) received a methylprednisolone infusion of 5.4 mg/kg per hour for 24 hours, those in the 48-hour regimen group (n=167) received a methylprednisolone infusion of 5.4 mg/kg per hour for 48 hours, and those in the tirilazad group (n=166) received a 2.5 mg/kg bolus infusion of tirilazad mesylate every 6 hours for 48 hours.

MAIN OUTCOME MEASURES

Motor function change between initial presentation and at 6 weeks and 6 months after injury, and change in Functional Independence Measure (FIM) assessed at 6 weeks and 6 months.

RESULTS

Compared with patients treated with methylprednisolone for 24 hours, those treated with methylprednisolone for 48 hours showed improved motor recovery at 6 weeks (P=.09) and 6 months (P=.07) after injury. The effect of the 48-hour methylprednisolone regimen was significant at 6 weeks (P=.04) and 6 months (P=.01) among patients whose therapy was initiated 3 to 8 hours after injury. Patients who received the 48-hour regimen and who started treatment at 3 to 8 hours were more likely to improve 1 full neurologic grade (P=.03) at 6 months, to show more improvement in 6-month FIM (P=.08), and to have more severe sepsis and severe pneumonia than patients in the 24-hour methylprednisolone group and the tirilazad group, but other complications and mortality (P=.97) were similar. Patients treated with tirilazad for 48 hours showed motor recovery rates equivalent to patients who received methylprednisolone for 24 hours.

CONCLUSIONS

Patients with acute spinal cord injury who receive methylprednisolone within 3 hours of injury should be maintained on the treatment regimen for 24 hours. When methylprednisolone is initiated 3 to 8 hours after injury, patients should be maintained on steroid therapy for 48 hours.

Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study

OBJECTIVE

To compare the efficacy of methylprednisolone administered for 24 hours with methyprednisolone administered for 48 hours or tirilazad mesylate administered for 48 hours in patients with acute spinal cord injury.

DESIGN

Double-blind, randomized clinical trial.

SETTING

Sixteen acute spinal cord injury centers in North America.

PATIENTS

A total of 499 patients with acute spinal cord injury diagnosed in National Acute Spinal Cord Injury Study (NASCIS) centers within 8 hours of injury.

INTERVENTION

All patients received an intravenous bolus of methylprednisolone (30 mg/kg) before randomization. Patients in the 24-hour regimen group (n=166) received a methylprednisolone infusion of 5.4 mg/kg per hour for 24 hours, those in the 48-hour regimen group (n=167) received a methylprednisolone infusion of 5.4 mg/kg per hour for 48 hours, and those in the tirilazad group (n=166) received a 2.5 mg/kg bolus infusion of tirilazad mesylate every 6 hours for 48 hours.

MAIN OUTCOME MEASURES

Motor function change between initial presentation and at 6 weeks and 6 months after injury, and change in Functional Independence Measure (FIM) assessed at 6 weeks and 6 months.

RESULTS

Compared with patients treated with methylprednisolone for 24 hours, those treated with methylprednisolone for 48 hours showed improved motor recovery at 6 weeks (P=.09) and 6 months (P=.07) after injury. The effect of the 48-hour methylprednisolone regimen was significant at 6 weeks (P=.04) and 6 months (P=.01) among patients whose therapy was initiated 3 to 8 hours after injury. Patients who received the 48-hour regimen and who started treatment at 3 to 8 hours were more likely to improve 1 full neurologic grade (P=.03) at 6 months, to show more improvement in 6-month FIM (P=.08), and to have more severe sepsis and severe pneumonia than patients in the 24-hour methylprednisolone group and the tirilazad group, but other complications and mortality (P=.97) were similar. Patients treated with tirilazad for 48 hours showed motor recovery rates equivalent to patients who received methylprednisolone for 24 hours.

CONCLUSIONS

Patients with acute spinal cord injury who receive methylprednisolone within 3 hours of injury should be maintained on the treatment regimen for 24 hours. When methylprednisolone is initiated 3 to 8 hours after injury, patients should be maintained on steroid therapy for 48 hours.

Systematic reviews of medical evidence: the use of meta-analysis in obstetrics and gynecology

OBJECTIVE

To review the technique of meta-analysis and its uses and limitations in obstetrics and gynecology.

DATA SOURCES

We reviewed four major journals in obstetrics and gynecology (American Journal of Obstetrics and Gynecology, Fertility and Sterility, Journal of Reproductive Medicine, and Obstetrics & Gynecology).

METHODS OF STUDY SELECTION

Journals were reviewed to determine frequency of meta-analysis as a method of systematic review in obstetrics and gynecology. We also summarized objectives and scientific guidelines for performing a meta-analysis.

TABULATION, INTEGRATION, AND RESULTS

Meta-analysis is used with increased frequency in obstetrics and gynecology as a way of systematically reviewing medical evidence. This technique is an attempt to improve on traditional methods of narrative review by an expert and as a framework for evidence-based medicine and developing practice guidelines. By combining data from replicate studies, a meta-analysis can increase statistical power, more precisely estimate the typical effect size of treatment or risk factor, and attempt to resolve controversies in the medical literature. Meta-analysis is a retrospective look at data already collected and is therefore subject to the biases of all retrospective studies.

CONCLUSIONS

The technique of meta-analysis requires all the scientific rigor of a randomized clinical trial with careful attention to study design, including a formal protocol for literature search strategies, quality assessment of candidate studies, specific inclusion and exclusion criteria, issues of sampling and publication bias, statistical tests of homogeneity, and sensitivity analysis.

Tree-based, two-stage risk factor analysis for spontaneous abortion

The authors utilize an analytic strategy that combines tree-based analyses with the method of Mantel-Haenszel to evaluate the association of 11 putative risk factors to spontaneous abortion by controlling for 19 potential confounders. Logistic regression is also used for comparison. The data for this study were collected in southern Connecticut, during 1988-1991. The putative risk factors are employment; standing, walking, or sitting more than 2 hours at work; exposure to vibration at work; commuting to work; reaching over the shoulders at work; carrying loads over 9 kg on the job; drinking alcohol or coffee in the first month of pregnancy; and gynecologic problems before pregnancy. The potential confounding factors are maternal age, marriage status, race, years of education mother's height, use of birth control, number of pregnancies, smoking before pregnancy, years of smoking, whether the mother stopped smoking, smoking marijuana, passive exposure to marijuana, chronic problems, infertility cocaine use and history of negative pregnancy outcomes. This analysis indicates that carrying loads over 9 kg on the job at least once a day increases the risk of spontaneous abortion by 70% (relative risk (RR) = 1.71, 95% CI 1.25-2.32). Drinking three or more cups of coffee daily in the first month of pregnancy also elevates the risk of spontaneous abortion (RR = 2.34, 95% CI 1.45-3.77). Reaching over the shoulders at least once daily has a marginally significant impact on spontaneous abortion (RR = 1.35, 95% CI 1.02-1.78). The authors conclude that this analytic strategy offers an efficient approach to the exploration of new risk factors for a disease where many potential confounders already exist.

Maternal caffeine consumption and spontaneous abortion: a prospective cohort study

We investigated the relation between caffeine beverage consumption and spontaneous abortion in 2,967 pregnant women planning to deliver at Yale-New Haven Hospital in 1988-1992. We evaluated coffee, tea, and soda drinking in the first month of pregnancy in interviews before the end of the sixteenth week of gestation. We obtained information on 98.2% of the pregnancies (including 2,714 singleton livebirths and 135 spontaneous abortions). As compared with abstention from caffeine beverages (coffee, tea, and soda), the adjusted odds ratios for spontaneous abortion associated with consumption of 1-150, 151-300, and > 300 mg caffeine daily were 0.81 [95% confidence interval (CI)) = 0.54-1.20], 0.89 (95% CI = 0.48-1.64), and 1.75 (95% CI = 0.88-3.47), respectively. Drinking > or = 3 cups of tea or coffee was associated with elevated risks of spontaneous abortion (adjusted odds ratio = 2.33, 95% CI = 0.92-5.85; and adjusted odds ratio = 2.63, 95% CI = 1.29-5.34, respectively). These results, if replicated, suggest that some ingredient (or correlate) of tea or coffee may account for some of the observed association of caffeine with spontaneous abortion. In this study, caffeine consumption is more strongly related to spontaneous abortion than alcohol or cigarette use in early pregnancy.