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PubMed2006

[Long-term impact of transfer of phrenic nerve on respiratory system of children: a clinical study of 34 cases].

OBJECTIVE: To study the long-term impact of transfer of phrenic nerve on respiratory system of children. METHODS: Thirty-four children with brachial plexus injury, 25 boys and 9 girls, underwent transfer of phrenic nerve and were divided into 3 groups according to the age when they underwent operation: group of the age of 0 - 12 months (n = 17), group of 13 - 36 months (n = 11), and group of 37 - 60 months (n = 6). Thirty-four sex, height, and body weight-matched healthy children were used as controls. Follow-up, including physical examination, pulmonary function examination (tidal volume, ventilation, etc), blood gas analysis, and chest radiography, was conducted for 4.03 years (3 - 7 years). RESULTS: The values of maximum vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 1.0 L +/- 0.2 L and 1.2 L +/- 0.4 L, both significantly lower than those of the corresponding control groups (1.3 L +/- 0.3 L and 1.4 L +/- 0.5 L, both P < 0.05). The values of one-second vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 0.8 L +/- 0.1 L and 0.9 L +/- 0.1 L, both significantly lower than those of the corresponding control groups (1.0 L +/- 0.1 L and 1.0 L +/- 0.1 L, both P < 0.05). However, the values of the maximum vital capacity and one-second vital capacity of the group of 37 - 60 months were 1.6 L +/- 0.3 L and 1.8 L +/- 0.5 L respectively, both not significantly different from those of the controls (both P > 0.05). The results of blood gas analysis of the 3 operation groups were not significantly different from those of the corresponding controls. Chest radiograph showed that the diaphragm top was raised by 1.93 intercostal spaces (0.5 - 3.5 intercostal spaces) in comparison with the contralateral sides with significant differences between the group of 0 - 12 months and the group of 13 - 36 months and between the group of 0 - 12 months and the group of 37 - 60 months (both P < 0.05). The recurrent respiratory infection rate and of the groups of 0 - 12 months and 13 - 36 months were 47.1% and 27.3% respectively, both significantly higher than that of the group of 37 - 60 months (0%). The thorax deformity rate of the groups of 0 - 12 months and 13 - 36 months were 41.2% and 9.1% respectively, both significantly higher than that of the group of 37 - 60 months (0%). Three of the children in the group of 0 - 12 months (17.6%) had digestive system symptoms. CONCLUSION: Transfer of phrenic nerve operated on children younger than 3 years may cause abnormalities of respiratory system, thorax, and digestive system. The younger the patients the more severe the consequences of the operation. The children older than 3 years tolerate the operation better.

Age Factors↗

PubMed1998

Relationship between estimated body fat and some respiratory function indices.

OBJECTIVE: To find the relationship between estimated body fat and respiratory function indices. DESIGN: Cross sectional study of volunteers in the physiotherapy department. SUBJECTS: Physiotherapy patients with no respiratory or neuromascular diseases. MAIN OUTCOME MEASURES: Quetelet index (as measure of body fat), vital capacity and breath holding time. RESULTS: Their ages ranged from 20 year to 60 years with a mean 24.20 +/- 6.59 years and 29.72 +/- 14.18 years in males and females respectively. Subjects whose quetelet index was about 30 kg/m2 and above were classified as obese. None of the male subjects fell into the obese category, while six of the 50 female subjects fell into the obese category. Significant differences were observed in the mean of the Quetelet index, percent predicted vital capacity and the breath holding time between the normal female and the obese female subjects. A high but inverse relationship was found between estimated body fat and each percent predicted vital capacity and breath holding time in subjects whose Quetelet index was above 30 kg/m2. There was also a high and positive correlation between percent predicted vital capacity and breath holding time in subjects with Quetelet index above 30 kg/m2. CONCLUSION: These findings were attributed to the restrictive effect of excess adipose tissue located around the thorax and the abdomen. It was concluded that adequate caution should be taken during exercise therapy for patients with a Quetelet index value above 30 kg/m2 to enable them exercise safely and with respiratory efficiency.

Adipose Tissue↗

PubMed1998

Three-dimensional volumetric assessment of abnormally low attenuation of the lung from routine helical CT: inspiratory and expiratory quantification.

OBJECTIVE: The purpose of this investigation was to quantitatively assess abnormally low attenuation of the lung by use of three-dimensional volumetric reconstructions from routine helical CT and to assess their correlation with pulmonary function tests. MATERIALS AND METHODS: Helical CT was performed in 100 patients in full inspiration. Examination was also performed in full expiration in 53 of these patients. Three-dimensional volumetric reconstructions were performed for total lung volumes at inspiration and at expiration, with a threshold of -896 H on inspiratory CT and -790 H on expiratory CT, to quantify emphysematous change. Correlation was made with pulmonary function tests in 79 patients. RESULTS: CT volumetric assessments of abnormally low attenuation of the lung at inspiration and expiration had a high correlation (r2 = .84, p < or = .0001). In comparison with pulmonary function tests, both inspiratory low attenuation of the lung and expiratory low attenuation of the lung correlated well with the logarithm of the ratio of the forced expiratory volume in 1 sec (FEV1) to the forced vital capacity (r2 = .74, p < or = .0001 and r2 = .74, p < or = .0001, respectively) and with the percentage of predicted ratio of the FEV1 to the forced vital capacity (r2 = .69, p < or = .0001 and r2 = .69, p < or = .0001, respectively). Linear correlations were also seen with FEV1, residual volume, and forced residual capacity. CONCLUSION: Three-dimensional volumetric reconstructions of hypoattenuating lung correlate well with pulmonary function tests. In addition, inspiratory and expiratory data are also correlative, suggesting that a dedicated expiratory examination is not needed. This easily obtainable information will prove useful for patients with obstructive lung disease from emphysema, providing a measure of pulmonary function status in this population.

Adolescent↗

PubMed2001

Ministernotomy versus complete sternotomy for coronary bypass operations: no difference in postoperative pulmonary function.

OBJECTIVES: Less-invasive approaches in cardiac operations offer certain cosmetic advantages, but it is unclear whether there are additional positive effects with regard to the postoperative recovery of patients. The aim of this prospective and randomized study was to ascertain whether partial inferior midline sternotomy can improve pulmonary function, one of the best quantifiable parameters of postoperative recovery, after coronary artery bypass operations when compared with the standard full midline approach. METHODS: One hundred patients scheduled for elective coronary artery bypass grafting were randomized either for a full median sternotomy (standard sternotomy group, n = 50) or for a partial inferior sternotomy (ministernotomy group, n = 50). The following pulmonary features were assessed: vital capacity, forced expiratory volume, percentage of forced expiratory volume from vital capacity, total lung capacity, residual volume, maximum inspiratory pressure, and maximum expiratory pressure. Tests were performed preoperatively and on the fourth and tenth postoperative days. RESULTS: On the fourth postoperative day, both groups had a significant decrease in vital capacity (percentage of predicted values) when compared with preoperative values (preoperative vs fourth day: standard sternotomy group, 87.8% +/- 14.3% vs 42.1% +/- 10.2% [P <.0001]; ministernotomy group, 84.5% +/- 14.3% vs 41.5% +/- 11.8% [P <.0001]), with a significant tendency for recovery from the fourth to the tenth postoperative day (fourth vs tenth postoperative day: standard sternotomy group, 42.1% +/- 10.2% vs 66.3% +/- 12.3% [P =.001]; ministernotomy group, 41.5% +/- 11.8% vs 61.3% +/- 13.1 % [P =.002]). There were no differences in any test results between the groups on either the fourth or the tenth postoperative day. CONCLUSION: A less-invasive approach for coronary artery bypass operations with a partial inferior sternotomy does not improve early postoperative pulmonary function when compared with the conventional approach with a full sternotomy.

Coronary Artery Bypass↗

PubMed1998

Lung reduction operation and resection of pulmonary nodules in patients with severe emphysema.

BACKGROUND: Severe pulmonary dysfunction has been considered a relative contraindication to surgical resection in patients with solitary pulmonary nodules. We report our initial experience with the combined use of lung volume reduction operation and tumor resection in this patient population. METHODS AND PATIENTS: Between January 1995 and July 1996, 14 patients underwent combined lung volume reduction operation and pulmonary nodule resection. Ten (71%) patients were oxygen dependent, 5 (36%) had a room air partial pressure of carbon dioxide > or = 45, and 5 (36%) were steroid dependent preoperatively. Mean preoperative pulmonary function tests included a forced expiratory volume in 1 second of 680 +/- 98 mL (24% +/- 5% predicted), forced vital capacity of 54% +/- 5% predicted, and a forced expiratory volume in 1 second to vital capacity ratio of 37% +/- 2% predicted. RESULTS: Sixteen lesions were resected in the 14 patients and included 9 non-small cell carcinomas. There was one postoperative death. All other patients are alive and well through a mean follow-up of 22.6 +/- 2.3 months (12 to 35 months). At 6-month follow-up improvements were noted in dyspnea index, forced expiratory volume in 1 second forced vital capacity, and 6-minute walk distance. Mediastinal recurrence at 12-month follow-up developed in 1 patient with two separate bronchioalveolar carcinomas. CONCLUSIONS: Simultaneous lung volume reduction operation and tumor resection should be considered in patients with emphysema with marginal reserve in the hope of maximizing postoperative lung function.

Aged↗

PubMed1995

Pulmonary function and posture in traumatic quadriplegia.

OBJECTIVE: To determine optimum posture for pulmonary function in traumatic quadriplegia. DESIGN: Lung function with changes in posture of normal healthy volunteers was compared with that of traumatic quadriplegic patients. MATERIALS AND METHODS: Functional residual capacity (FRC), Forced vital capacity (FVC), and arterial blood gases in room air were compared in 16 male patients aged 18 to 32 years, 8 of whom (group I) sustained traumatic quadriplegia (C6 to C7) at least 1 year previously, and 8 of whom (group II) were healthy volunteers. MEASUREMENTS: FRC, FVC and blood gases were measured after 15 minutes in the following random positions: 20 degrees head down, horizontal, 35 degrees head up, 60 degrees head up, and 90 degrees head up. MAIN RESULTS: FRC was lower in all positions in group I but there was a similar directional change in FRC with posture in both groups. The greatest increase in FRC occurred in group I between the 35-degree head up and the 60-degree head up positions. Group I, in contrast to group II, decreased FVC from the 35-degree head up to the 60-degree head up position. There were no significant changes in PO2 with position in group II, but quadriplegic patients showed PO2 improvement from the head down to the horizontal and 60-degree head up positions. CONCLUSIONS: In traumatic quadriplegia, maximum oxygenation and patency of alveoli (FRC) are achieved in the 60- to 90-degree head up positions. In contrast to normal subjects, no changes in FRC and FVC occurred between the horizontal and 35-degree head up positions in quadriplegia. The optimum position in these patients for physiotherapy (deep breathing and coughing, as reflected by maximum FVC) is the horizontal or 35-degree head up position. These differences in lung volumes and oxygenation with posture may be important in optimizing respiratory care in traumatic quadriplegia.

Adult↗

PubMed1990

Comparison of four methods of preoxygenation.

We studied four different techniques of preoxygenation in 20 healthy volunteers, by continuous analysis of respired gases. Three minutes of tidal breathing from a Magill breathing system or four vital capacity breaths from a non-rebreathing system were found to be equally effective, whereas four vital capacity breaths from a Magill breathing system were less effective. Maximal expiration before application of the face mask resulted in improved oxygenation when four vital capacity breaths were taken from a Magill system.

Adult↗

PubMed1985

Effects of mitral valve replacement on ventilation, volumes, diffusing capacity and regional perfusion of lungs in patients with mitral valve disease.

The effects of mitral valve replacement on ventilation, lung volumes, diffusing capacity and regional perfusion of the lungs were studied in eight patients with long-standing mitral valve disease. Eight patients of the same age with coronary artery disease who underwent coronary bypass operation were tested as controls. Preoperatively, the patients with mitral valve disease had significantly higher perfusion of the upper lung fields and the ratio of residual volume to total lung capacity than the control patients. Vital capacity, forced expiratory volume in one second and maximal expiratory flow at 50% of vital capacity were lower in comparison with the control group. Seven days after open heart surgery the values of all the parameters mentioned above had decreased significantly from the preoperative levels in both groups. Three months post-operatively, the values returned to preoperative levels. The abnormal overperfusion of the upper lung fields and other derangements in the ventilatory pattern did not subside even though cardiac haemodynamics were corrected by mitral valve replacement.

Adult↗

PubMed1990

Determinants of restrictive lung function in asbestos-induced pleural fibrosis.

We evaluated whether restrictive lung function among asbestos-exposed individuals with pleural fibrosis was caused by radiographically inapparent parenchymal inflammation and/or parenchymal fibrosis. All 24 study participants were sheet metal workers who were nonsmokers with normal parenchyma on posteroanterior chest radiograph. These subjects had either normal pleura (n = 7), circumscribed plaques (n = 9), or diffuse pleural thickening (n = 8). After controlling for age, years in the trade, and pack-years of smoking, we found that sheet metal workers with diffuse pleural thickening had a lower forced vital capacity (P less than 0.001), total lung capacity (P less than 0.01), and CO-diffusing capacity of the lung (P less than 0.05) than those with normal pleura. Similarly, sheet metal workers with circumscribed plaques were found to have a reduced forced vital capacity; however, because of the small number of study subjects, this difference (regression coefficient = -11.0) was only marginally significant (P = 0.06). Although circumscribed plaque and diffuse pleural thickening were both associated with a lymphocytic alveolitis and a higher prevalence of parenchymal fibrosis on high-resolution computerized tomography (HRCT) scan, neither a lymphocytic alveolitis nor the finding of parenchymal fibrosis on HRCT scan influenced the relationship between pleural fibrosis and restrictive lung function. We conclude that pleural fibrosis is associated with restrictive lung function and abnormally low diffusion that appears to be independent of our measures of parenchymal injury (chest X-ray, bronchoalveolar lavage, and HRCT scan).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1975

Post-operative epidural analgesia: effects on lung volumes.

A study was undertaken to assess the role of post-operative pain in reducing Functional Residual Capacity (FRC) and Vital Capacity (VC). The efficacy of post-operative epidural analgesia in reversing these changes was measured in eight subjects after upper abdominal operations. With pain, FRC and VC were 78 per cent and 37 per cent of control respectively. Following epidural analgesia, the values were 84 per cent and 55 per cent. These figures indicate the pain component in the post-operative reduction of these two lung capacities. This partial restoration may be of value in the prevention of post-operative pulmonary complications by avoiding closure of small airways during tidal breathing and by increasing the effectiveness of deep breathing and coughing in the removal of secretions and the reversal of atelectasis.

Adult↗

PubMed1982

Effects of ipratropium bromide and fenoterol aerosols in pulmonary emphysema.

In patients with radiological evidence of pulmonary emphysema the bronchodilator drugs fenoterol and ipratropium bromide produced a considerable increase in vital capacity and reduction in residual volume. The response to fenoterol was virtually complete 15 minutes after administration, but after ipratropium bromide vital capacity was still increasing at 60 minutes. The change in vital capacity was slightly greater with a combination of the two drugs than with either used alone. Changes in FEV1 and peak flow rate were small.

Aerosols↗

PubMed1992

Recovery of pulmonary diffusing capacity after maximal exercise.

Pulmonary diffusing capacity (DICO), together with spirometric variables, arterial oxygen tension (paO2) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and ergometer rowing. Independent of the type of exercise, D1CO increased immediately post-exercise from a median 13.6 (range 7.3-16.3) to 15.1 (9.3-19.6) mmol min-1 kPa-1 (P < 0.01). However, it decreased to 11.6 (6.9-15.5) mmol min-1 kPa-1 (P < 0.01) after 24 h with cardiac output and paO2 at resting values, and D1CO normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post-exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in D1CO. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0-47.0) to 47.1 (42.7-49.8) (P < 0.01), had normalized at the time of the decrease in D1CO. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid-expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0-7.6) to 7.0 (5.1-7.8) litres (P < 0.05) immediately after exercise and remained elevated at 6.9 (5.1-8.7) litres (P < 0.05) when a decrease in D1CO was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15% reduction in D1CO takes place 2-3 h post-exercise, which normalizes during the following day of recovery.

Adult↗

PubMed1979

Changes in pulmonary function after naturally acquired respiratory infection in normal persons.

Changes in pulmonary function due to naturally occurring respiratory tract infection were examinated in 26 normal healthy volunteers during a period of 6 months. Forced expiratory maneuvers in each volunteer were recorded at 2-wk intervals throughout the study and daily during illness. Significant impairment of peak expiratory flow rate, forced vital capacity, forced expiratory volume in one second, and maximal mid-expiratory flow rate at 50% of the vital capacity was observed during infection, whereas changes in the maximal expiratory flow rate at 75% of vital capacity were nonsignificant. From these results, we conclude that large airways are certainly affected during uncomplicated respiratory infections in normal healthy persons and from the changes observed in FVC we suggest that more widespread involvement of the small airways may occur.

Adolescent↗

PubMed2001

How can we best read exhaled nitric oxide flow curves in asthmatic children?

Orally exhaled nitric oxide (NO) levels are increased in children with asthma and thought to reflect the local inflammatory events in the airways. NO production in the lower respiratory airway is reflected in the plateau values of the NO curve, recorded while the patient is performing a slow vital capacity manoeuvre. In young patients, however, plateau values may be difficult to obtain, because the slow vital capacity manoeuvre is often terminated prematurely. In the present study, 60 steroid-naive atopic asthmatic children and 17 normal age-matched controls were asked to perform a slow vital capacity manoeuvre, during which fractional exhaled NO (FEno) levels were measured and evaluated as: a) FEno plateau levels of last part of exhalation (NO plateau); b) FEno peak values, c) area under the FEno curve (AUC). Thirteen out of the 60 steroidnaive patients were reevaluated after a short course of inhaled corticosteroid treatment. Independently of the type of data analysis, FEno values of asthmatics were significantly higher than those observed in normal controls (P < 0.001, each comparison). In addition, possibly because of upper airway NO contamination, FEno peak values were significantly higher than FEno plateau levels in asthmatic patients and in control subjects (P < 0.001, each comparison). Both in asthmatics and controls, highly positive correlations were observed between: a) FEno plateau and peak values (r > 0.7, P < 0.01, each correlation), b) FEno plateau and AUC values (r > 0.7, P < 0.01, each correlation) and c) FEno peak and AUC values (r > 0.9, P < 0.001, each correlation). In asthmatic patients, the three types of data analysis were equally sensitive in detecting the decrease in FEno levels induced by inhaled steroid therapy (P < 0.05, each comparison), with a good correlation between the three data analyses (r > 0.5, P < 0.05, each correlation). Thus, although quantitatively different, comparable data reflecting airway inflammation can be obtained evaluating FEno plateau, FEno peak, and area under the curve, on account of possible upper airway contamination in FEno peak, FEno plateau should be preferred to measure lower airway NO production.

Adolescent↗

PubMed2000

[Different responses of right and left ventricular diastolic function to pulmonary resection: echocardiographic study with leg elevation for preload augmentation].

OBJECTIVES: The effects of pulmonary resection on cardiac function have not been well characterized. This study used Doppler echocardiography to evaluate preoperative and postoperative right and left ventricular function with preload augmentation by elevation of the legs. METHODS: Twenty-one patients (12 males, 9 females, mean age 64 +/- 11 years) undergoing pulmonary resection for lung cancer underwent concurrent examination of cardiac and pulmonary function at 1 week preoperation and 4 weeks postoperation. Cardiac function of right and left ventricles was assessed by Doppler echocardiography to record waveforms of transtricuspid flow and transmitral flow. Assessment was made in the supine position and with leg elevation 60 degrees to apply preload augmentation. We measured the interval between cessation and onset of transatrioventricular flow, ventricular ejection time and Tei index as an index of global ventricular function. Peak velocity of early filling (E) and atrial contraction (A) were measured from the transtricuspid and transmitral flows to calculate E/A of the right and left ventricles (ER/AR, EL/AL). Pulmonary function tests yielded the forced vital capacity expressed as the ratio to the predicted value as an index for the pulmonary vascular bed area. RESULTS: The postoperative cardiac function without preload augmentation was comparable to the preoperation function. With preload augmentation, the postoperative ER/AR was less than preoperation in the patients with postoperative forced vital capacity < or = 80% of the preoperation value. There was a significant correlation between the postoperation versus preoperation ratio of ER/AR and of forced vital capacity (r = 0.66, p = 0.0028) and ratio of right ventricular Tei index and of forced vital capacity (r = 0.61, p = 0.0034). There was a possibility that right ventricular Tei index indirectly indicated the state of pulmonary vascular bed area. CONCLUSIONS: The right ventricular Tei index is useful to estimate preoperation and postoperation global right ventricular function. No close relationship between ER/AR and EL/AL at preoperation (r = 0.70, p = 0.0004) was found in the patients with postoperative right ventricular Tei index > 0.1 greater than at preoperation. Pulmonary resection might affect the diastolic function of the right ventricle more than the left ventricle, possibly because of reduced compliance of the right ventricle indicated by an increased atrial contraction at postoperation with preload augmentation.

Diastole↗

PubMed1984

[Diffuse pulmonary carcinomatous lymphangitis. Study of respiratory function in 18 cases].

Respiratory function studies were carried out in 18 patients with diffuse and isolated pulmonary lymphangitis (LCP) diagnosed on radiological and cyto-histological grounds. Restrictive ventilatory defects were found in 17 out 18 cases CPT: 75,3% (DS = 5), CV: 56.7% (DS = 14,5). The Tiffeneau coefficient was less than 65% in 50% of cases but the DEM/CV was reduced in 77% of cases, evidence of the great frequency of airflow obstruction. The measure of the (formula; see text) was normal in 5 out of 17 cases, implying the absence of an alveolar neoplastic lesion or obliteration by arteritis or capillaritis in LCP. The alveolar-arterial oxygen gradient on hyperoxia was normal (less than 27 kPa) 14 times out of 18 and slightly increased in 4. Important hypoxaemia at rest was present 17 times out of 18; PaO2: 8 kPa (DS = 1). There was no patient with alveolar hyperventilation: PaCO2: 4.3 kPa (DS = 0.5). On exercise, hypoxaemia remained stable 4 times, improved 5 times and worsened 9 times. A pathophysiological interpretation was given for each disturbance of respiratory function. In conclusion, a characteristic respiratory function profile of LCP is proposed, with a restrictive ventilatory disturbance or moderate mixed picture, a DLCO/VA ratio generally normal, almost constant hypoxaemia at rest and improvement or worsening on exercise. CPT = Mean total lung capacity. CV = Mean vital capacity. DS = Standard deviation.

Aged↗

PubMedDate not supplied

[Flow-volume curves in healthy children and adolescents 10-19 years of age. Reference values and lower limits of the normal].

In 477 healthy children and adolescents (247 boys and 230 girls, aged 10 to 19 years), we measured the vital capacity (VC), the forced expiratory volume in one second (FEV1), the flow between 25 and 75% of expired forced vital capacity (FEF25-75) and the forced expiratory flows when 75, 50 and 25% of forced vital capacity remain to be expired (FEF75, FEF50, FEF25), in order to determine reference values and lower limits of the normal. Regression functions were calculated for girls and boys separately. The best correlations for pulmonary volumes and flows were obtained by taking into account simultaneously height and age in girls, height, age and weight in boys. Power function is the model of regression that fits our data the best. The regression functions determined, as well as the lower limits of the normal and the residual standard deviations, are given by sex for each of the variables measured. These results are discussed and compared with those in literature. They concern clinicians (identification of "abnormal" subjects) and epidemiologists (prevalence of ventilatory troubles, comparison of different populations), and can be used in adolescents of the same age groups.

Adolescent↗

PubMed2002

Dietary magnesium, potassium, sodium, and children's lung function.

To investigate the effects of dietary magnesium, potassium, and sodium on children's lung function, the authors examined cross-sectional dietary data and pulmonary function tests from 2,566 children aged 11-19 years who attended schools in 12 southern California communities during 1998-1999. During school visits, each child completed a health update questionnaire, a validated food frequency questionnaire, and spirometric lung function testing. Low magnesium and potassium intakes were associated with lower lung function. Girls with low magnesium intake had lower forced expiratory flow at 75% of the forced vital capacity (FEF(75)) (-8.3%, 95% confidence interval: -14.8, -1.4) than did girls with higher intake; reductions were larger in girls with asthma (forced expiratory flow between 25% and 75% of the forced vital capacity (FEF(25-75)) (-16.2%, 95% confidence interval: -22.7, -9.1) and FEF(75) (-24.9%, 95% confidence interval: -32.8, -16.1)) than in girls without asthma (FEF(25-75) (-2.0%, 95% confidence interval: -7.4, 3.8) and FEF(75) (-4.1%, 95% confidence interval: -11.3, 3.7)). Boys with low magnesium intake showed deficits in forced vital capacity (-2.8%, 95% confidence interval: -5.4, -0.2) compared with boys with higher intake. The effects of low magnesium intake did not vary substantially in boys with and without asthma. Among girls, low potassium intake was also associated with deficits in forced expiratory volume in 1 second (-2.7%, 95% confidence interval: -5.2, -0.1) and forced vital capacity (-2.4%, 95% confidence interval: -4.7, -0.1). In summary, low magnesium and potassium intakes were associated with lower lung volumes and flows.

Adolescent↗