Evaluation of the global lung function initiative 2012 reference values for spirometry in a Swedish population sample

BACKGROUND

The Global Lung Function Initiative 2012 (GLI) reference values are currently endorsed by several respiratory societies but evaluations of applicability for adults resident in European countries are lacking. The aim of this study was to evaluate if the GLI reference values are appropriate for an adult Caucasian Swedish population.

METHODS

During 2008-2013, clinical examinations including spirometry were performed on general population samples in northern Sweden, in which 501 healthy Caucasian non-smokers were identified. Predicted GLI reference values and Z-scores were calculated for each healthy non-smoking subject and the distributions and mean values for FEV1, FVC and the FEV1/FVC ratio were examined. The prevalence of airway obstruction among these healthy non-smokers was calculated based on the Lower Limit of normal (LLN) criterion (lower fifth percentile) for the FEV1/FVC ratio. Thus, by definition, a prevalence of 5% was expected.

RESULTS

The Z-scores for FEV1, FVC and FEV1/FVC were reasonably, although not perfectly, normally distributed, but not centred on zero. Both predicted FEV1 and, in particular, FVC were lower compared to the observed values in the sample. The deviations were greater among women compared to men. The prevalence of airway obstruction based on the LLN criterion for the FEV1/FVC ratio was 9.4% among women and 2.7% among men.

CONCLUSIONS

The use of the GLI reference values may produce biased prevalence estimates of airway obstruction in Sweden, especially among women. These results demonstrate the importance of validating the GLI reference values in different countries.

Passive smoking exposure is associated with increased risk of COPD in never smokers

BACKGROUND

Passive smoking, or environmental tobacco smoke (ETS), is a risk factor for lung cancer, cardiovascular disease, and childhood asthma, but a relationship with COPD has not been fully established. Our aim was to study ETS as a risk factor for COPD in never smokers.

METHODS

Data from three cross-sectional studies within the Obstructive Lung Disease in Northern Sweden (OLIN) database were pooled. Of the 2,182 lifelong never smokers, 2,118 completed structured interviews and spirometry of acceptable quality. COPD was defined according to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) criteria using postbronchodilator spirometry. The association of COPD with ETS in single and multiple settings was calculated by multivariate logistic regression adjusting for known risk factors for COPD.

RESULTS

COPD prevalence was associated with increased ETS exposure: 4.2% (no ETS), 8.0% (ETS ever at home), 8.3% (ETS at previous work), and 14.7% (ETS ever at home and at both previous and current work), test for trend P = .003. Exclusion of subjects aged ≥ 65 years and subjects reporting asthma yielded similar results. ETS in multiple settings, such as ever at home and at both previous and current work, was strongly associated to COPD (OR, 3.80; 95% CI, 1.29-11.2).

CONCLUSIONS

In this population-based sample of never smokers, ETS was independently associated with COPD. The association was stronger for ETS in multiple settings. ETS in multiple settings was, after age, the strongest risk factor for COPD and comparable to personal smoking of up to 14 cigarettes/d in comparable materials. The findings strongly advocate measures against smoking in public places.

Prevalence trends in respiratory symptoms and asthma in relation to smoking - two cross-sectional studies ten years apart among adults in northern Sweden

Background

Smoking is considered to be the single most important preventable risk factor for respiratory symptoms. Estimating prevalence of respiratory symptoms is important since they most often precede a diagnosis of an obstructive airway disease, which places a major burden on the society. The aim of this study was to estimate prevalence trends of respiratory symptoms and asthma among Swedish adults, in relation to smoking habits. A further aim was to estimate the proportion of respiratory symptom and asthma prevalence attributable to smoking.

Methods

Data from two large-scale cross-sectional surveys among adults performed in northern Sweden in 1996 and 2006 were analysed. Identical methods and the same questionnaire were used in both surveys. The association between smoking, respiratory symptoms and asthma was analysed with multiple logistic regression analyses. Changes in prevalence of respiratory symptoms and asthma from 1996 to 2006 were expressed as odds ratios. Additionally, the population attributable risks of smoking were estimated.

Results

The prevalence of most respiratory symptoms decreased significantly from 1996 to 2006. Longstanding cough decreased from 12.4 to 10.1%, sputum production from 19.0 to 15.0%, chronic productive cough from 7.3 to 6.2%, and recurrent wheeze from 13.4 to 12.0%. Any wheeze and asthmatic wheeze remained unchanged. This parallels to a decrease in smoking from 27.4 to 19.1%. In contrast, physician-diagnosed asthma increased from 9.4 to 11.6%. The patterns were similar after correction for confounders. All respiratory symptoms were highly associated with smoking, and the proportion of respiratory symptoms in the population attributed to smoking (PAR) ranged from 9.8 to 25.5%. In 2006, PAR of smoking was highest for recurrent wheeze (20.6%).

Conclusions

In conclusion, we found that respiratory symptoms, in particular symptoms common in bronchitis, decreased among adults in northern Sweden, parallel to a decrease in smoking from 1996 to 2006. In contrast, the prevalence of physician-diagnosed asthma increased during the same time-period. Up to one fourth of the respiratory symptom prevalence in the population was attributable to smoking.

Health economic costs of COPD in Sweden by disease severity--has it changed during a ten years period?

OBJECTIVES

The objectives of the presented study were to estimate societal costs of COPD in Sweden, the relationship between costs and disease severity, and possible changes in the costs during the last decade.

METHODS

Subjects with COPD derived from the general population in Northern Sweden were interviewed by telephone regarding their resource utilisation and productivity losses four times quarterly during 2009-10. Mean annual costs were estimated for each severity stage of COPD.

RESULTS

A strong relationship was found between disease severity and costs. Estimated mean annual costs per subject of mild, moderate, severe and very severe COPD amounted to 596 (SEK 5686), 3245 (SEK 30,957), 5686 (SEK 54,242), and 17,355 euros (SEK 165,569), respectively. The main cost drivers for direct costs were hospitalisations (for very severe COPD) and drugs (all other severity stages). The main cost driver for indirect costs was productivity loss due to sick-leave (for mild COPD) and early retirement (all other severity stages). Costs appeared to be lower in 2010 than in 1999 for subjects with severe and very severe COPD, but higher for those with mild and moderate COPD.

CONCLUSION

Our results show that costs of COPD are strongly related to disease severity, and scaling the data to the whole Swedish population indicates that the total costs in Sweden amounted to 1.5 billion euros (SEK 13.9 bn) in 2010. In addition, costs have decreased since 1999 for subjects with severe and very severe COPD, but increased for those with mild and moderate COPD.

COPD among non-smokers - report from the obstructive lung disease in Northern Sweden (OLIN) studies

BACKGROUND

In westernized countries smoking and increasing age are the most important risk factors for COPD. Prevalence and risk factors of COPD among non-smokers are not well studied.

AIM

To study the prevalence and risk factors of COPD among non-smokers and to determine the proportion of non-smokers among subjects with COPD.

METHODS

A random sample of 2470 subjects drawn from a population-based postal survey of 10,040 (85-88% participation) adults (aged 20-77) in Norrbotten, Sweden, were invited to structured interviews and lung function tests, and 1897 participated. COPD was classified using the fixed ratio (GOLD) definition and for comparison the lower limit of normal (LLN).

RESULTS

The prevalence of airway obstruction was 6.9% among non-smokers and strongly age related. The prevalence of GOLD stage ≥II among non-smokers was 3.5%. Both among subjects with airway obstruction and among subjects with GOLD stage ≥II, the proportions of non-smokers were 20%. Of men with airway obstruction, 14.1% were non-smokers versus 26.8% among women. Non-smokers with GOLD stage ≥II had significantly more symptoms and higher co-morbidity than non-smokers without airway obstruction. Sex, area of domicile and exposure to environmental tobacco smoke was not significantly associated to airway obstruction among non-smokers. Using LLN for defining airway obstruction yielded a similar prevalence.

CONCLUSION

The prevalence of airway obstruction among non-smokers was close to 7% and was associated with increasing age. One out of seven men with airway obstruction, defined using the fixed ratio, versus one out of four women had never smoked.

Effect of adjuvant androgen deprivation on thyroid function tests in prostate cancer patients

Androgen deprivation (AD) used in the treatment of prostate cancer is known to alter concentrations of sex hormones and their binding globulins. Less is known as to its effect on thyroid hormones. In this prospective study the effects of AD on thyroid function were clarified. Levels of serum thyroid stimulating hormone (TSH), free thyroxine (FT4) and thyroid binding globulin concentrations were measured in prostate cancer patients treated with either radical radiotherapy and androgen deprivation for 12 months (AD) or radical radiotherapy alone (RT). Measurements were made at baseline, and at 3, 6 and 12 months. At baseline and at 3 months the results of thyroid function tests did not differ significantly between groups. A significant decline in serum testosterone in the AD group was accompanied by a significant decline in FT4 at 6 and 12 months, while no significant changes in thyroid function were observed in the RT group. The decline in FT4 among AD patients did not evoke a normal TSH response. Prolonged use of AD hampers the interpretation of thyroid test results. This finding has substantial implications for the follow-up of patients in hormonally treated prostate cancer.

Androgen deprivation and cognition in prostate cancer

Androgen deprivation (AD) is commonly used in neoadjuvant and adjuvant setting with prostate cancer (PC) radiotherapy. This prospective study assessed whether cognitive functioning is impaired during 12 months of AD therapy. Longitudinal testing of 25 patients treated with AD and curative radiotherapy was undertaken at baseline, and at 6 and 12 months. CogniSpeed software was used for measuring attentional performances. Other cognitive performances were evaluated using verbal, visuomotor and memory tests. The Beck depression inventory was employed to evaluate depressive mood and EORTC QLQ-C30 for quality of life (QoL). During longitudinal testing of the AD group, no impairment in cognitive performances was found. Instead, improvement was observed in object recall (immediate, P=0.035; delayed, P<0.001), and in semantic memory (P=0.037). In QoL, impairment in physical function was observed. Androgen deprivation of 12 months appears to be associated with preserved cognitive functioning, although physical impairment occurs. These results have implications for counseling and psychosocial support of patients in the context of treatment options in PC.

DNA cytometry in diagnostic cytology of the prostate gland

BACKGROUND

Differential analysis and cytological grouping of fine needle aspiration biopsy (FNAB) samples of the prostate are important in practice. We used image analytical DNA cytometry to achieve this and also studied the best method of interpretation of the histograms.

MATERIALS AND METHODS

Sixty-two FNAB samples of the prostate were stained with Feulgen stain and nuclear DNA histograms were produced by image cytometry. The most atypical cell groups were selected for measurements. Also, free epithelial cells between cell groups were studied. The cells presented in the histograms were grouped according to the nuclear DNA content and by application of different gates of observation for diploid status.

RESULTS

Several DNA histogram features (histogram classification categories, benign and malignant histogram patterns, presence of >5c-7c cells) showed significant relationships to differential diagnosis. Highly aneuploid (>5c-7c) cells had the potential for distinguishing a progressive-type of prostate cancer.

CONCLUSION

The fraction of tetraploid and aneuploid histograms increased from atypical but benign to definitely malignant samples. DNA histograms have potential in the differential diagnosis and evaluation of the progressive character of prostate cancer.

Air quality and ocular discomfort aboard commercial aircraft

BACKGROUND

Aircraft cabin air quality has been a subject of recent public health interest. Aircraft environments are designed according to standards to ensure the comfort and well-being of the occupants. The upper and lower limits of humidity set by ASHRAE standards are based on the maintenance of acceptable thermal conditions established solely on comfort considerations, including thermal sensation, skin wetness, skin dryness, dry eyes and ocular discomfort. The purpose of this study is to investigate the influence of air (carbon dioxide level, relative humidity, and temperature) aboard commercial aircraft on ocular discomfort and dry eye of aircraft personnel and passengers.

METHODS

Measurements of indoor air quality were performed in 15 different aircraft at different times and altitudes. Forty-two measurements of carbon dioxide, temperature, and humidity were performed with portable air samplers every 5 minutes. Passenger loads did not exceed 137 passengers.

RESULTS

Thermal comfort rarely met ASHRAE standards. Low humidity levels and high carbon dioxide levels were found on the Airbus 320. The DC-9 had the highest humidity level and the Boeing-767 had the lowest carbon dioxide level.

CONCLUSIONS

Air quality was poorest on the Airbus 320 aircraft. This poor level of air quality may cause intolerance to contact lenses, dry eyes, and may be a health hazard to both passengers and crew members. Improved ventilation and aircraft cabin micro-environments need to be made for the health and comfort of the occupants.

Indoor-air quality and ocular discomfort

BACKGROUND

Almost 25 million workers in 1.2 million commercial buildings in the United States have symptoms of sick building syndrome (SBS). It is a source of ocular discomfort and may exacerbate the successful wear of contact lenses. This study examines the relationship between SBS and oculovisual discomfort.

METHODS

Measurements of carbon dioxide, formaldehyde, temperature, and humidity were performed in 12 public office buildings that contained a total of 877 occupants. A questionnaire survey of the occupants was also performed.

RESULTS

Thirty-five percent of the occupants of the buildings were dissatisfied with the indoor-air quality. Twenty-nine percent of the office building occupants reported ocular discomfort.

CONCLUSION

There was a significant correlation between eye irritation, throat irritation, and symptoms of blurred near vision. Ocular discomfort could be an indicator of poor indoor-air quality and a sick building syndrome.

Validity of ambulatory 24-h oesophageal pH measurement in the diagnosis of reflux disease

The validity of 24-h oesophageal pH recording was studied in 100 consecutive patients who had gastro-oesophageal reflux (GER) symptoms and had indications for a 24-h pH recording. The aim was to explore the relationship of patient symptoms, endoscopic findings and histopathological analysis of oesophageal mucosa with the findings in pH recording. Among these patients with typical GER symptoms, the multiplicity of symptoms or their nature did not differentiate them, but in all groups abnormal amounts of reflux were present, as compared with usual reference pH recording values. Yet, among these symptomatic patients, the macroscopic severity of oesophagitis and histologically defined oesophagitis were related to increased abnormality of 24-h pH recording. The results suggest that 24-h pH recording of the oesophagus gives a good indication of the severity of gastro-oesophageal reflux disease and, as such, superior to patient symptoms.

Diurnal changes in dopamine-beta-hydroxylase, homovanillic acid and 3-methoxy-4-hydroxyphenylglycol in serum of man

Dopamine-beta-hydroxylase activity (DBH) and concentrations of homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured in serum of 11 normal volunteers at 8 a.m., 2 p.m., 8 p.m. and 2 a.m. DBH was higher at 8 a.m. (p less than 0.05) and lower at 2 a.m. (p less than 0.0025). MHPG followed the same course, while HVA was higher at 8 p.m. (p less than 0.05). The mean values for the eleven volunteers were: DBH 65.8+/-25.8 nanomoles hydroxylated tyramine per ml serum and hour (At substrate concentration 0.05 mM), HVA 89.9+/-57.3 ng/ml serum and MHPG 10.9+/-3.4 ng/ml, with variation coefficient of 38.6, 63.8 and 30.1 respectively. The circadian variations found in serum parallel the data from estimations of MHPG and HVA in urine by other investigators. It is suggested that the diurnal variations of DBH, MHPG and HVA reflect the alternating activity of the catecholaminergic neurons in the peripheral as well as the central nervous system.