The Prevalence of Asthma and Respiratory Symptoms among Cross-Country Skiers in Early Adolescence.

Objective: To determine the prevalence of asthma and respiratory symptoms among Swedish cross-country skiers in early adolescence in comparison to a population-based reference group of similar ages. Methods: A postal questionnaire on asthma, asthma medication, allergy, respiratory symptoms, and physical activity was distributed to Swedish competitive cross-country skiers aged 12-15 years (n = 331) and a population-based reference group (n = 1000). The level of asthma control was measured by the Asthma Control Test. Results: The response rate was 27% (n = 87) among skiers and 29% (n = 292) in the reference group. The prevalence of self-reported asthma (physician-diagnosed asthma and use of asthma medication in the last 12 months) and the prevalence of reported wheezing during the last 12 months were 23% and 25%, respectively, among skiers, which were significantly higher than the values reported in the reference group (12% and 14%). Skiers exercised more hours/week than the reference group. Among adolescents with self-reported asthma, neither the usage of asthma medications nor the level of asthma control according to the Asthma Control Test differed between skiers and the reference group. Conclusions: Adolescent competitive cross-country skiers have an increased prevalence of respiratory symptoms and asthma compared to nonskiers.

B12 deficiency is common in infants and is accompanied by serious neurological symptoms.

AIM: Adverse neurological symptoms have been linked to vitamin B12 deficiency in infants. This explorative study described the clinical presentation associated with vitamin B12 deficiency in this age group. METHODS: The study comprised infants who were born between 2004 and 2012 and were tested for vitamin B12 levels after they were admitted to a hospital with neurological symptoms at less than one year of age. Vitamin B12 deficiency was defined as low cobalamin in serum and/or increased homocysteine and/or increased methylmalonate. It was diagnosed according to the applicable International Classification of Diseases, 10th revision, and recorded as vitamin B12 deficiency in the medical records. All information was retrieved from medical records and compared to symptomatic infants with normal levels. RESULTS: Of the 121 infants tested, 35 had vitamin B12 deficiency and 86 had normal levels. Vitamin B12 deficiency was diagnosed at an average age of 1.7 months and was more common among boys. Seizures and apparent life-threatening events were the most common symptoms among infants with B12 deficiency compared to infants with normal levels. CONCLUSION: Vitamin B12 deficiency was more common in infants than we expected and presented with severe symptoms, such as seizures and apparent life-threatening events.

Enhanced monsoon precipitation and nitrogen deposition affect leaf traits and photosynthesis differently in spring and summer in the desert shrub Larrea tridentata.

Leaf-level CO2 assimilation (A(area)) can largely be predicted from stomatal conductance (g(s)), leaf morphology (SLA) and nitrogen (N) content (N(area)) in species across biomes and functional groups. The effects of simulated global change scenarios, increased summer monsoon rain (+H2O), N deposition (+N) and the combination (+H2O +N), were hypothesized to affect leaf trait-photosynthesis relationships differently in the short- and long-term for the desert shrub Larrea tridentata. During the spring, +H2O and +H2O +N plants had lower A(area) and g(s), but similar shoot water potential (Psi(shoot)) compared with control and +N plants; differences in A(area) were attributed to lower leaf N(area) and g(s). During the summer, +H2O and +H2O +N plants displayed higher A(area) than control and +N plants, which was attributed to higher Psi(shoot), g(s) and SLA. Throughout the year, A(area) was strongly correlated with g(s) but weakly correlated with leaf N(area) and SLA. We concluded that increased summer monsoon had a stronger effect on the performance of Larrea than increased N deposition. In the short term, the +H2O and +H2O +N treatments were associated with increasing A(area) in summer, but also with low leaf N(area) and lower A(area) in the long term the following spring.

Supplementary oxygen and risk of childhood lymphatic leukaemia.

AIM: Childhood leukaemia has been linked to several factors, such as asphyxia and birthweight, which in turn are related to newborn resuscitation. Based on the findings from a previous study a population-based case-control study was performed to investigate the association between childhood leukaemia and exposure to supplementary oxygen and other birth-related factors. METHODS: Children born in Sweden and diagnosed with lymphatic leukaemia between 1973 and 1989 (578 cases) were individually matched by gender and date of birth to a randomly selected control. Children with Down's syndrome were excluded. Exposure data were blindly gathered from antenatal, obstetric and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated by conditional logistic regression. RESULTS: Resuscitation with 100% oxygen with a facemask and bag immediately postpartum was significantly associated with an increased risk of childhood lymphatic leukaemia (OR = 2.57, 95% Cl 1.21-6.82). The oxygen-related risk further increased if the manual ventilation lasted for 3 min or more (OR = 3.54, 95% CI 1.16-10.80). Low Apgar scores at 1 and 5 min were associated with a non-significantly increased risk of lymphatic leukaemia. There were no associations between lymphatic leukaemia and supplementary oxygen later in the neonatal period or other birth-related factors. CONCLUSION: Resuscitation with 100% oxygen immediately postpartum is associated with childhood lymphatic leukaemia, but further studies are warranted to confirm the findings.

Intrauterine exposure to diagnostic X rays and risk of childhood leukemia subtypes.

The relationship between childhood leukemia and prenatal exposure to low-dose ionizing radiation remains debatable. This population-based case-control study investigated the association between prenatal exposure to diagnostic X-ray examinations (for different types of examinations and at different stages of pregnancy) and the risk of childhood lymphatic and myeloid leukemia. All children born and diagnosed with leukemia between 1973-1989 in Sweden (578 lymphatic and 74 myeloid) were selected as cases, and each was matched (by sex and year of birth) to a healthy control child (excluding Down's syndrome). Exposure data were abstracted blindly from all available medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression. It was found that prenatal X-ray examinations resulting in direct fetal exposure were not associated with a significant overall increased risk for childhood leukemia (OR = 1.11, 95% CI 0.83-1.47), for lymphatic leukemia (OR = 1.04, 95% CI 0.77-1.40), or for myeloid leukemia (OR = 1.49, 95% CI 0.48-4.72). There was little evidence of a dose response or variation in risk by trimester of exposure or age at diagnosis. Thus X-ray examinations performed during pregnancy in the 1970s and 1980s in Sweden did not affect the risk of childhood leukemia discernibly.

Photosynthetic sunfleck utilization potential of understory saplings growing under elevated CO2 in FACE.

Few studies have evaluated elevated CO2 responses of trees in variable light despite its prevalence in forest understories and its potential importance for sapling survival. We studied two shade-tolerant species (Acer rubrum, Cornus florida) and two shade-intolerant species (Liquidambar styraciflua, Liriodendron tulipifera) growing in the understory of a Pinus taeda plantation under ambient and ambient+200 ppm CO2 in a free air carbon enrichment (FACE) experiment. Photosynthetic and stomatal responses to artificial changes in light intensity were measured on saplings to determine rates of induction gain under saturating light and induction loss under shade. We expected that growth in elevated CO2 would alter photosynthetic responses to variable light in these understory saplings. The results showed that elevated CO2 caused the expected enhancement in steady-state photosynthesis in both high and low light, but did not affect overall stomatal conductance or rates of induction gain in the four species. Induction loss after relatively short shade periods (<6 min) was slower in trees grown in elevated CO2 than in trees grown in ambient CO2 despite similar decreases in stomatal conductance. As a result leaves grown in elevated CO2 that maintained induction well in shade had higher carbon gain during subsequent light flecks than was expected from steady-state light response measurements. Thus, when frequent sunflecks maintain stomatal conductance and photosynthetic induction during the day, enhancements of long-term carbon gain by elevated CO2 could be underestimated by steady-state photosynthetic measures. With respect to species differences, both a tolerant, A. rubrum, and an intolerant species, L. tulipifera, showed rapid induction gain, but A. rubrum also lost induction rapidly (c. 12 min) in shade. These results, as well as those from independent studies in the literature, show that induction dynamics are not closely related to species shade tolerance. Therefore, it cannot be concluded that shade-tolerant species necessarily induce faster in the variable light conditions common in understories. Although our study is the first to examine dynamic photosynthetic responses to variable light in contrasting species in elevated CO2, studies on ecologically diverse species will be required to establish whether shade-tolerant and -intolerant species show different photosynthetic responses in elevated CO2 during sunflecks. We conclude that elevated CO2 affects dynamic gas exchange most strongly via photosynthetic enhancement during induction as well as in the steady state.

Fetal tachycardia: intrauterine and postnatal course.

Eighteen consecutive cases of fetal tachycardia referred to the department of Pediatric Cardiology, Uppsala University, were studied retrospectively. All cases were detected at a routine visit at an antenatal clinic. None of the cases had a structural heart disease. Fetal supraventricular tachycardia was found in 8 cases and atrial flutter in 10 cases. In 7 cases, hydrops and heart failure were diagnosed. Antenatal treatment with digoxin, alone or in combination with other antiarrhythmic drugs, was needed in 15 cases. In 10 cases an obvious effect of the therapy was observed. No intrauterine deaths occurred. One infant died postnatally. At birth, 4 infants were in need of neonatal intensive care when delivered. Antiarrhythmic treatment was started in 13 cases postnatally. Late relapse of tachycardia was reported in 3 children. In 1 of these cases the prenatal tachycardia had resolved spontaneously and the infant was not treated antenatally nor during the neonatal period. Although fetal tachycardia is a serious condition, antenatal treatment in combination with careful monitoring and induction of delivery in cases with deteriorating fetal condition result in a satisfactory outcome for the majority of infants. However, there is a risk of late recurrence.

Codeine and the breastfed neonate.

Codeine is an analgesic commonly used to relieve pain in the early post partum. Its metabolite, morphine, is probably responsible for its effectiveness in this use. However, morphine may also cause neonatal apnea. We studied free codeine and morphine levels in breastmilk of 17 samples from seven mothers and neonatal plasma of 24 samples from 11 healthy, term neonates. Levels were determined by radioimmunoassay. Milk codeine levels ranged from 33.8 to 314 ng/ml 20 to 240 minutes after codeine; morphine levels ranged from 1.9 to 20.5 ng/ml. Infant plasma samples one to four hours after feeding had codeine levels ranging from < 0.8 to 4.5 ng/ml; morphine ranged from < 0.5 to 2.2 ng/ml. Low infant plasma levels are secondary to low excretion into milk and the small amounts of milk available in the first few days. Moderate codeine use during this time (< or = four 60 mg doses) is probably safe.

Racial differentials in the identification of hypercholesterolemia.

BACKGROUND: African Americans have higher rates of cardiovascular disease than white Americans. To address this differential, barriers to cardiovascular risk reduction need to be identified. This study examines the association of race with the likelihood of screening for and diagnosis of hypercholesterolemia. METHODS: Possible associations between demographic variables and screening for and diagnosis of hypercholesterolemia were examined on data gathered in a prospective fashion in an office-based family medicine residency training program in Rochester, New York. A consecutive sample of all patients seen between December 15, 1988, and April 15, 1990, about whom there was complete data collection (age, sex, insurance, race, and other cardiovascular risk factors) were included in the multivariate analyses (N = 4256). RESULTS: After controlling for age, sex, insurance status, socioeconomic status, number of visits, and other cardiovascular risk factors, it was found that minorities were less likely to have been screened for cholesterol levels than whites (adjusted odds ratio [AOR] = 0.84, 95% confidence interval [CI] = 0.98 to 0.72). The mean cholesterol level did not differ by race (mean cholesterol for whites, 204 mg/dL [5.28 mmol/L], and for minorities, 203 mg/dL [5.25 mmol/L], t = 0.7, P = .47). Among those screened, minorities were less likely than whites to have been diagnosed with hypercholesterolemia (AOR = 0.62, 95% CI = 0.86 to 0.44; and 0.47 (95% CI = 0.28 to 0.78] in those with a cholesterol level greater than 240 mg/dL [6.2 mmol/L]). CONCLUSIONS: Our data suggest that provider behavior in diagnosing hypercholesterolemia varies by the race of the patient.

Voices from family medicine: toward the 21st century. Interview by William B. Ventres and John J. Frey.

Throughout STFM's 25th anniversary year, we illustrated the dynamic history of family medicine using the personal narratives of some of the discipline's founders and early leaders. We have attempted to take the energy of their spoken words and put it on paper for clinician educators to learn from and lead by. For us, as authors, this process has been enriching and has caused us to reexamine and confirm the meanings of our roles as teachers in family medicine. In this final installment, we present five new voices: individuals from succeeding generations of academic family physicians. Like the many others we interviewed but have not included here, these five individuals were identified by colleagues for their demonstrated leadership in the discipline. They and others will help mold the future of family medicine well into the 21st century.

Barriers to cholesterol testing in a rural community.

BACKGROUND: The purpose of this study was to investigate the factors that determine whether residents in a rural community have their cholesterol tested. METHODS: A population-based survey was conducted in 1987 as part of a community-oriented primary care project that sought to define and address the causes of and burden caused by increased cardiovascular disease in an economically depressed agricultural region of New York. All of the residents living in two towns in the region who were over 16 years of age and who lived in their homes year-round were surveyed. Demographic information was obtained from the participants, as well as information about previous cholesterol testing and their cardiovascular-risk knowledge and behaviors. The serum cholesterol of each participant was measured. RESULTS: Of the 557 households contacted, 508 (91%) households participated. A total of 1063 persons over 16 years of age were surveyed, and 973 (92%) were screened for cholesterol. Overall, 24% reported prior cholesterol testing. Logistic regression analysis identified several independent factors that were associated with a reduced likelihood of ever having had a cholesterol test. These factors included: (1) age under 45 years, (2) having less than 12 years of education, (3) having an income of less than $10,000, (4) not having health insurance, (5) not having visited a physician within the previous year, and (6) practicing three or more high-risk cardiovascular behaviors. The participants' cardiovascular knowledge made no independent contribution to having had their cholesterol levels tested. CONCLUSIONS: Many of the factors that prevent cholesterol testing are socially determined. The results of this study suggest that financial and social barriers are two of the major obstacles to residents of rural communities having their cholesterol levels tested.

Sudden infant death and home monitors.

During a two-year period, ten infants died suddenly and unexpectedly with a home cardiorespiratory monitor available. We investigated the compliance with appropriate monitoring technique as well as the medical and demographic factors associated with these deaths (90% were due to sudden infant death syndrome). At least six and probably eight of these ten families were noncompliant with appropriate monitoring technique. The main comparison group consisted of 211 patients for whom care with home cardiorespiratory monitors was initiated and continued. Bronchopulmonary dysplasia and severe, apparent life-threatening events were significantly increased in the subjects, as were the following characteristics: black race; lack of private medical insurance; unmarried mother; maternal age of less than 25 years; cigarette smoking by mother during pregnancy; and low Apgar scores. These diagnostic and demographic factors may be useful in predicting the infant at highest risk for sudden and unexpected death when a home monitor is prescribed. Noncompliance with proper monitoring technique patients; methods of educating parents of infants at high risk of sudden infant death syndrome with the necessity for compliance need to be developed.