Prevalence and mechanisms of development of asthma and airway hyperresponsiveness in athletes

A high prevalence of asthma and airway hyperresponsiveness (AHR) has been reported in the athlete population. Factors potentially predisposing athletes to these conditions have not been clearly identified. Although moderate exercise has been shown to be beneficial in patients with asthma, repeated high-intensity exercise could possibly contribute to the development of asthma and AHR. This report provides an overview of the prevalence and possible mechanisms of development of asthma and AHR in the athlete population. The prevalence of asthma and AHR are higher in athletes than in the general population, particularly in swimmers and athletes performing sports in cold air environments. Possible mechanisms involved in the development of asthma in athletes are still uncertain; however, the content and physical characteristics of the inhaled air seem to be important factors, while immune and neurohumoral influences could play a modulatory role. This report stresses the need for further studies to better define the aetiologic factors and mechanisms involved in the development of asthma and AHR in athletes, and proposes relevant preventive and therapeutic measures.     

HBs Ag and antibodies to hepatitis C virus in complicated chronic liver disease in Gabon. A case control study

BACKGROUND AND OBJECTIVE: The prevalence of HBs Ag and anti-HCV antibodies are high in the general population in Gabon. The aim of this study was to perform a case control study to determine the role of hepatitis B and C viruses in decompensated cirrhosis and hepatocellular carcinoma. METHODS: Between October 1990 and June 1998, HBs Ag and anti-HCV antibodies were investigated in 1 204 newly hospitalized patients. Sixty-seven had decompensated cirrhosis, 38 had hepatocellular carcinoma and six an association of both diseases. Prevalences were compared with those in a group of 527 sex and age matched controls from the same cohort. RESULTS: HBs Ag prevalence among cases was 35.1% (decompensated cirrhosis: 34.2%; hepatocellular carcinoma: 40.5%) and 12.5% among controls. Anti-HCV were detected in 32.4% of cases (decompensated cirrhosis: 34.2%; hepatocellular carcinoma: 28.6%) and in 20.1% of controls. Complicated chronic liver disease was linked to HBs Ag (OR=11.3; IC: 4.8-26.7; cirrhosis: OR=18; IC: 5.3-61.5; hepatocellular carcinoma: OR=8.3; IC: 2.5-27.8) in patients from 15 to 34 years old. Above 45 years, complicated chronic liver disease was linked to anti-HCV antibodies (OR=2.9; IC: 1.6-5.3; cirrhosis: OR=2.8; IC: 1.4-5.8; hepatocellular carcinoma: OR=3.2; IC: 1.1-9.5). CONCLUSION: Both Hepatitis B and C viruses are linked to complicated chronic liver disease in Gabon in an age-dependent manner.     

Lower airway inflammatory responses to high-intensity training in athletes

PURPOSE: There is an increased prevalence of asthma and airway hyperresponsiveness in elite athletes, particularly in swimmers. High intensity exercise may induce airway inflammation and subsequent remodelling in these subjects. Our aim was to evaluate the effects of high-intensity training on induced-sputum cell populations in elite athletes. METHODS: Swimmers and runners with hyperresponsive airways (SH and RH), defined by a provocative concentration of methacholine inducing a 20% decrease in FEV1 (PC20) <16 mg/ml or with normoresponsive airways (PC20 > 16 mg/ml; SN, RN) to methacholine were enrolled. The mean PC20 was 2.27 mg/ml in SH (n=12), 32.2 in SN (n=10), 3.25 in RH (n=10) and 41.5 in RN (n=13). All athletes had two induced sputum analyses at one- to two-week intervals in random order: after a period of 72 hours without training, 24 hours after a training session. RESULTS: PC20 was unchanged after training. The median % neutrophils and eosinophils in groups SH, SN, RH, and RN, respectively, were 26.5-1.6, 8.6-0.3, 28.0-0.03 and 25.5-0.1 before and 45.0-0.5, 31.1-0.4, 54.0-0.6 and 48.3-0.3 after training. While the magnitude of the increase in neutrophils was similar for all groups, it reached statistical significance (pre-post-training) only in the SH group (P = 0.039). CONCLUSION: A one-hour session of high-intensity training was associated with an increase in airway neutrophils among hyperresponsive swimmer athletes, while airway responsiveness remained unchanged in all groups.     

Airway hyperresponsiveness in elite athletes

It has been suggested that high-level training could contribute to the development of airway hyperresponsiveness (AHR), but the comparative effects of different sports on airway function remains to be determined. We evaluated 150 nonsmoking volunteers 18 to 55 yr of age; 100 athletes divided into four subgroups of 25 subjects each according to the predominant estimated hydrocaloric characteristic of ambient air inhaled during training: dry air (DA), cold air (CA), humid air (HA) and a mixture of dry and humid air (MA), and 50 sedentary subjects. Each subject had a respiratory questionnaire, a methacholine challenge, allergy skin-prick tests, and heart rate variability recording for evaluation of parasympathetic tone. The athletes had a 49% prevalence of AHR (PC(20) < 16 mg/ml), with a mean PC(20) of 16.9 mg/ml, compared with 28% (PC(20): 35.4) in sedentary subjects (p = 0.009). The prevalence (%) of AHR and mean PC(20) (mg/ml) varied as followed in the four subgroups of athletes: DA: 32% and 30.9; CA: 52% and 15.8; HA: 76% and 7.3; and MA: 32% and 21.5 (p = 0.002). The estimated parasympathetic tone was higher in athletes (p < 0.001), but this parameter showed only a weak correlation with PC(20) (r = -0.17, p = 0.04). This study has shown a significantly higher prevalence of AHR in athletes than in the control group because of the higher prevalence in the CA and HA groups. Parasympathetic activity may act as modulator of airway responsiveness, but the increased prevalence of AHR in our athlete population may be related to the type and possibly the content of inhaled air during training.     

Psychiatric Patients: How Can We Decide if You Are in Pain?

How do psychiatric nurses make decisions about pain management for hospitalized psychiatric patients? This is the question addressed by this research. Using an exploratory, naturalistic interview approach, 20 nurses and managers in varied settings described their decision making when providing pain relief. Analysis of these narratives indicates that decision making about pain, in this unique context, is influenced by a number of intrapersonal and interpersonal factors such as the patients' needs, history, and diagnosis; nurses' beliefs about pain tolerance and drug addiction; collegial pressure; and unit safety. For example, diagnosis and patient history impact pain relief negatively, while the responsibility to maintain a safe environment imposes pressure to administer medication. Although, in a psychiatric unit, the nurse-patient relationship is essential to the healing process, nurses often face a dilemma as to whether the pain medication will contribute to healing or exacerbate the patient's issues. In psychiatric wards, the means of recovery are far less clear, tangible, and immediate than in other clinical settings. Recommendations are made for better preparing and supporting nurses to work effectively in these practice settings where pain relief is confounded by addiction and psychiatric diagnoses.     

Influence of sympatho-vagal balance on airway responsiveness in athletes

The increased prevalence of airway hyper-responsiveness (AHR) observed among athletes suggests that high-level training may contribute to the development of AHR. We investigated the possible influence of the sympatho-vagal balance on this phenomenon in 40 athletes and 10 sedentary controls. Each subject filled out a respiratory questionnaire, had a methacholine challenge, and measurements were made of their baseline plasma catecholamines [epinephrine (E), norepinephrine (NE) and dopamine (DA)] as a reflection of sympathetic tone, and their heart rate variability (SDNN: standard deviation of all normal-to-normal intervals) as an indicator of parasympathetic tone. The athletes had a 45% prevalence of AHR (defined as PC₂₀ < 16 mg/ml, where PC₂₀ is the concentration of methacholine inducing a 20% fall in the forced expiratory volume in 1 s, FEV₁) with a mean PC₂₀ of 21.2 mg/ml compared with 10% prevalence (mean PC₂₀: 74.4 mg/ml) in sedentary subjects (P < 0.01). Plasma catecholamine values were not significantly different between the two groups (all P > 0.05), but the estimated parasympathetic tone was higher in athletes (P=0.01). When data from all subjects were analyzed together, plasma E and NE correlated with PC₂₀ (r=0.39, P=0.005 and r=0.29, P < 0.005) but DA and SDNN did not (both P > 0.05). However, the ratios E/SDNN, NE/SDNN and DA/SDNN showed significant correlations with PC₂₀ (r=0.42, P < 0.01; r=0.33, P < 0.005 and r=0.31, P < 0.05, respectively). This study suggests that the sympatho-vagal balance may contribute to the increased AHR in the population studied but this influence alone cannot explain the higher prevalence of AHR in athletes. Accepted: 26 July 2000     

Prevalence of respiratory symptoms in an athlete population

This study aimed to look at the prevalence and type of respiratory symptoms experienced by athletes and to assess the possible influence on the perception of symptoms of training duration and environment. A group of 698 athletes (107 with diagnosed or self-reported asthma) filled out a questionnaire on their respiratory condition. They exercised either in cold air (n = 176), dry air (n = 384), humid air (n = 95) or mixed dry and humid air (n = 43). Past exercise-related symptoms reported by athletes were breathlessness (48.7%), phlegm production (22.8%), wheezing (15.6%), cough (15.2%), and chest tightness (7.4%). Only 25% of asthmatic athletes reported having current exercise-induced symptoms of breathlessness, 21.7%, wheezing and 17.4%, chest tightness; current exercise-induced symptoms of breathlessness, wheezing or chest tightness were also reported, respectively, in 38.9%, 3.6% and 2.7% of athletes without a diagnosis of asthma. The perception of exercise-induced symptoms was not influenced by the duration of training or environment. In conclusion, (1) a minority of asthmatic athletes report troublesome respiratory symptoms with exercise, (2) breathlessness is not more frequently reported in asthmatic athletes than in those without such diagnosis while cough and wheezing are more common in asthmatic subjects and (3) the prevalence of respiratory symptoms is independent of training environment and duration of training.     

Is asthma over- or under-diagnosed in athletes?

A high prevalence of asthma has been reported in athletes. However, studies in this population usually show an even higher prevalence of airway hyperresponsiveness (AHR) and exercise-induced bronchoconstriction (EIB). This report compares studies on self-reported or physician-diagnosed asthma in athletes with those using objective measures of airflow limitation or airway responsiveness. The higher prevalence of AHR (or EIB) measured in athletes, when compared with the prevalence of self-reported or physician-diagnosed asthma, suggests that abnormal airway responses are common in athletes, although they are infrequently associated with troublesome respiratory symptoms. This may indicate underdiagnosis of asthma in athletes, possibly due to an underreporting of respiratory symptoms or a reduction in perception of nociceptive sensations with repeated exercise over time, or it may simply mean that high-level training is associated with asymptomatic AHR. In athletes, as in the general population, the use of subjective methods such as surveys and questionnaires results in an underestimation ofthe prevalence of airway dysfunction when compared with objective measurements. The significance of these observations is unknown, and there is a need to determine their long-term consequences for athletes.