Trend and Seasonality of Hip Fractures in Catalonia, Spain: Exploring the Influence of Climate

To describe the secular trend and seasonality of the incidence of hip fracture (HF) and its relationship with climatic variables during the period 2010-2019 in Catalonia in people aged ≥ 65 years. The results were analyzed by sex, age groups (65-74, 75-84, and ≥ 85), and types of fracture (extracapsular and intracapsular). Data on sex, age, type of fracture, year, and month of hospitalization of patients admitted with a diagnosis of HF between January 1, 2010 and December 31, 2019 were collected. Crude and standardized HF incidence (HFi) rates were obtained. Data on the monthly mean of climatological variables (temperature, insolation, icy days, rain, relative humidity, atmospheric pressure, and wind force) were obtained from the network of meteorological stations in Catalonia. Time series analytical statistics were used to identify trends and seasonality. Linear regression and a seasonal autoregressive integrated moving average (ARIMA) were used to analyze the relationship of each climatic parameter with fracture rates. In addition, generalized additive models were used to ascertain the best predictive model. The total number of HF episodes was 90,149 (74.1% in women and 25.9% in men). The total number of HFs increased by 6.4% between 2010 and 2019. The median age (SD) was 84.5 (7.14) and 54% of patients were ≥ 85 years of age. Extracapsular fractures were the most common (55%). The standardized incidence rates decreased from 728.1/100,000 (95% CI 738.6-769.3) to 624.5/100,000 (95% CI 648.7-677.0), which represents a decrease of 14.2% (p < 0.05). The decline was greater at older ages. There were seasonal variations, with higher incidences in autumn (27.2%) and winter (25.7%) and lower rates in summer (23.5%) and spring (23.6%). Seasonality was more pronounced in elderly people and men. In the bivariate regression analysis, high temperatures and greater insolation were negatively associated with the HF rate, while the number of icy days, rainy days, and high relative humidity were associated with a higher incidence of fractures in all age groups and sexes. In the regression analysis using the seasonal ARIMA model, only insolation had a consistently significant association with overall HFi, after adjusting by trend and other climatic parameters. While the global number of HFs grew in Catalonia due to increases in the elderly population, the standardized HF rate decreased during the years 2010-2019. There was a seasonal trend, with predominance in the cold months and correlations with climatic parameters, especially with insolation.

Prevalence and 3-year incidence of physical illnesses after schizophrenia diagnosis: Comparison with general population

AIM

People with schizophrenia are at a greater risk of poor physical health than the general population. This study investigated the annual incidence of physical illnesses after a new schizophrenia diagnosis, which has rarely been investigated in the literature.

METHODS

The authors collected data from Taiwan's National Health Insurance Research Database from January 1, 1996, to December 31, 2013, and enrolled 1910 patients with newly diagnosed schizophrenia cases aged 10-40 years and 7640 age- and sex-matched controls from the general population. They estimated the 1-year prevalence and annual incidence rate ratio (IRR) of specified physical diseases across 3 years in the schizophrenia group compared with the controls.

RESULTS

Several physical illnesses were prevalent within 1 year of schizophrenia diagnosis. Regarding incident physical illnesses, patients had a moderate to strong risk of numerous physical illnesses (IRR > 3.0: ischemic heart disease, cerebrovascular disease, diabetes mellitus, and cancer; IRR 1.8-3.0: other forms of heart disease, vein and lymphatic diseases, pneumonia, chronic hepatic disease, and ulcer disease) within the first year after schizophrenia diagnosis. The IRRs of most physical illnesses declined over 3 years, except for that of cerebrovascular disease, which significantly increased (IRR > 3.0) over the 3 years after schizophrenia diagnosis. Cerebrovascular disease had a significant incidence risk (IRR > 3) persistently across the 3 years.

CONCLUSION

Various comorbid physical illnesses can occur in the early stages of schizophrenia. Clinicians should consider these vulnerabilities to physical illnesses during the evaluation of patients with newly diagnosed schizophrenia by attempting to prevent, screen for, and manage them.

Increased incidence of rheumatoid arthritis after COVID-19

An increase in the incidence of inflammatory arthritis after COVID-19 has been reported. Since many diseases exhibit population-specific causal effect sizes, we aimed to evaluate the incidence trends of inflammatory arthritis, including rheumatoid arthritis (RA), after COVID-19 in a large admixed Colombian population. Data analysis for this retrospective, population-based cohort study was carried out using the COOSALUD EPS registry. The following codes were selected for analyses: M059, seropositive RA, M069, unspecified RA, M060 seronegative RA, and other RA-related diagnoses: M064, M139, M068, M058, M130 and M053. The study period was limited to January 01, 2018, through December 31, 2022. Incidence rates (IRs) and incidence rate ratios (IRRs) were assessed. A Cox survival model was built to evaluate the influence of age, gender, and COVID-19 vaccination status on the development of inflammatory arthritis. A bioinformatic analysis was performed to evaluate the homology between SARS-CoV-2 and autoantigen peptides related to RA. The entire population study comprised 3,335,084 individuals. During the pandemic period (2020-2022) the total IIR for seropositive and unspecified RA were 1.60 (95% CI, 1.16-2.22) and 2.93 (95% CI, 2.04-4.19), respectively, and the IIR for overall RA-related diagnosis was 2.01 (95% CI 1.59-2.53). The age groups hazard ratios (HRs) were increased until the age group of 51-60 years (HR: 9.16; 95% CI, 7.24-11.59) and then decreased slightly in the age group 61 years or older (HR: 5.364; 95% CI, 4.24-6.78) compared to those within 18-30 years. Men were less at risk than women to develop inflammatory arthritis (HR: 0.21; 95% CI, 0.18-0.24). The greater time since COVID-19 diagnosis was associated with a lower likelihood of developing inflammatory arthritis (HR: 0.99; 95% CI:0.998-0.999). Vaccination (all types of COVID-19 vaccines included) did not prevent the development of inflammatory arthritis after COVID-19. Low identity was found between the SARS-CoV-2 ORF1ab antigen and the human antigens Poly ADP-ribose polymerase 14 and Protein mono-ADP-ribosyltransferase PARP9 isoform D (39% and 29%, respectively). In conclusion, our study confirms increased incidence of inflammatory arthritis, including RA, after COVID-19, with the greatest increase occurring before the first year post-covid. Women in their fifties were more susceptible. Further research is required to examine the effectiveness of vaccination in preventing post-COVID inflammatory arthritis and the mechanisms implicated in the development of RA after COVID-19.

Impact of decompensated cirrhosis in children: A population-based study

Background

We describe the proportion of children with compensated cirrhosis who develop decompensation in Ontario, Canada over the past two decades.

Methods

This is a retrospective population-based cohort study using routinely collected health care data from Ontario, Canada held at ICES during 1997-2017. Diagnosis of cirrhosis was made using validated ICES definition, and decompensation events were defined according to validated coding. Rates of decompensation, type of decompensation, and incidence of liver transplantation after decompensation were analyzed. Databases were linked at the individual level and analyzed at ICES-Queen's.

Results

A total of 2,755 children with compensated cirrhosis were included and 9% (253) developed decompensation over a median follow-up of 7 years. Children most likely to suffer decompensation were younger (median age 10 versus 4 years, p < 0.001) and female (45% versus 52%, p = 0.03). Ascites (137/253, 54%) was the most frequent complication. 199/2755 (7%) of children with cirrhosis received liver transplantation, of which 64% (128/199) occurred after a decompensation event. Overall, a total of 132 (4.7%) deaths occurred during the study period, with 55 deaths following a decompensating event.

Conclusion

We present the first study to describe rates of decompensation, type, and rate of liver transplantation after decompensation in pediatric cirrhosis at the population level. To improve the care of children with liver disease, early detection of liver disease, early initiation of specific treatments as well as identification of children who are at risk of becoming decompensated are crucial.

Disparities in oesophageal cancer risk by age, sex, and nativity in Kuwait:1980-2019

BACKGROUND

This cross-sectional cohort study assessed the inequalities in oesophageal carcinoma risk by age, sex and nativity in Kuwait: 1980-2019.

METHODS

Using oesophageal cancer incidence data from the Kuwait National Cancer Registry, relevant Kuwaiti population data and World Standard Population as a reference, age-standardized incidence rates (ASIR) (per 100,000 person-years) overall and by subcohorts were computed. The incident oesophageal cancer cases count was overdispersed with excessive structural zeros, therefore, it was analyzed using multivariable zero-inflated negative binomial (ZINB) model.

RESULTS

Overall ASIR of oesophageal cancer was 10.51 (95% CI:  6.62-14.41). The multivariable ZINB model showed that compared with the younger age category (< 30 years), the individuals in higher age groups showed a significant (p < 0.001) increasing tendency to develop the oesophageal cancer.  Furthermore, compared with the non-Kuwaiti residents, the Kuwaiti nationals were significantly (p < 0.001) more likely to develop oesophageal cancer during the study period. Moreover, compared with 1980-84 period, ASIRs steadily and significantly  (p < 0.005) declined in subsequent periods till 2015-19.

CONCLUSIONS

A high incidence of oesophageal cancer was recorded in Kuwait, which consistently declined from 1980 to 2019. Older adults (aged ≥ 60 years) and, Kuwaiti nationals were at high risk of oesophageal cancer. Focused educational intervention may minimize oesophageal cancer incidence in high-risk groups in this and other similar settings. Future studies may contemplate to evaluate such an intervention.

Effectiveness of patient and staff cohorting to reduce the risk of vancomycin-resistant enterococcus (VRE) acquisition: a retrospective cohort study during a VRE outbreak in Japan

BACKGROUND

Patient and staff cohorting is part of a bundle approach in the response to multi-drug-resistant organisms, but its effectiveness is not fully clarified. This study compared the risks of acquiring vancomycin-resistant Enterococcus faecium (VREfm) at a hospital during a VREfm outbreak based on contact characteristics in order to better understand the effectiveness of cohorting.

METHODS

Exposure came from contact with patients with VREfm (infectors), including existing patients with VREfm and patients who acquired VREfm during the study period. Contact was defined as length of contact time, degree of sharing space, and care by the same nurses as those caring for infectors between January and March 2018. The outcome was VREfm acquisition as determined through monthly stool or rectal screening cultures. Incidence rates were calculated based on contact patterns, and incidence rate ratios (IRRs) were compared.

FINDINGS

Among 272 inpatients (4038 patient-days), 43 patients acquired VREfm with the same or similar pulsotype. Incidence rates were 8.45 per 1000 patient-days when susceptible inpatients were on the same ward as an infector but cared for by different nurses (reference), 16.96 when susceptible inpatients were on the same ward as an infector and cared for by the same nurses [IRR 2.01, 95% confidence interval (CI) 0.62-10.28], and 52.91 when susceptible inpatients shared a room with an infector (IRR 6.26, 95% CI 1.61-35.40).

CONCLUSION

Compared with susceptible inpatients in a different room from infectors and not being cared for by the same nurses, the risk of VREfm acquisition could be six times higher for susceptible inpatients who are in the same room as infectors, and could be double for susceptible inpatients cared for by the same nurses as infectors.

Analysis of all non-fatal self-harm cases in an urban area of Japan during pre- and peri-pandemic periods of COVID-19: a population-based study

BACKGROUND

This study aimed to examine population-based characteristics of non-fatal self-harm in an urban area during pre- and peri-pandemic periods of COVID-19 by sex, age, and severity of self-harm, using pre-hospital medical emergency records.

METHODS

We used a registry of all pre-hospital medical records of self-harm cases that occurred in Kawasaki City, Japan, between January 2018 and December 2021. Adjusted incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated using Poisson regression models with the log-transformed population by year, sex, age group, and ward as an offset term.

RESULTS

During the 4-year study period, 1,534 patients were transported by ambulance due to non-fatal self-harm and were alive on arrival at the hospital. Among women, the number of non-fatal self-harm cases increased by 1.2-fold in 2021 compared with that in 2018. The incidence rate of "severe" non-fatal self-harm among men aged 19 years or younger in 2021 (IRR 4.82, 95% CI 1.25-18.65) and that among women aged 50-59 years in 2020 (IRR 2.51, 95% CI 1.06-5.95) significantly increased compared with that 2018 and 2019. The incidence rate of "mild" self-harm among women aged 20-29 years tended to be higher in 2021 than in 2018 and 2019 (IRR 1.42, 95% CI 0.95-2.12, P = 0.085).

CONCLUSIONS

During the peri-pandemic period of COVID-19, the incidence rate of "severe" non-fatal self-harm among men aged 19 years or younger and women aged 50-59 years, as well as that of "mild" self-harm among women aged 20-29 years, sharply increased compared with that during the pre-pandemic period. Our findings suggest that in urban areas during public health crises such as a pandemic, it is important to take measures to reduce the risk of non-fatal self-harm in young women, in addition to strengthening counseling and support for young women at risk for completed suicide.

Association of knowledge and attitudes with practices of misuse of tranquilizers: A cohort study in Spain

BACKGROUND

Tranquilizer misuse represents a growing international public health problem with heavy social and economic consequences. We aimed to identify the psychosocial determinants of this misuse practice, focusing on modifiable factors including knowledge and attitudes towards these medications.

METHODS

A prospective cohort study involving 847 adults accompanying children in primary care clinics was carried out in Spain. A validated Knowledge, Attitudes and Practices (KAP) questionnaire on tranquilizer use was self-administered at baseline, and then participants were followed-up bimonthly. A misuse event was defined as unprescribed intake of tranquilizers, storing/sharing leftovers of tranquilizers, and/or not adhering to the prescribed treatment period, timing or dosage. Poisson regression models were applied to estimate adjusted Incidence Rate Ratios (IRRs) of misuse and their 95 % Confidence Intervals (CIs).

FINDINGS

Individuals' personal attitudes towards tranquilizers and treating physicians are strongly associated with the misuse of these drugs. These attitudes include: individuals' acceptance of taking tranquilizers to improve sleeping [IRR: 5.10 (95 %CI: 2.74-9.48)], to work better [IRR: 2.04 (95 %CI: 1.05-3.99)], or for recreational purposes [IRR: 1.85 (95 %CI: 1.04-3.32)]; willingness to prolong the course of tranquilizer treatment without medical consultation [IRR: 2.45 (95 %CI: 1.46-4.13)]; agreeing on storing tranquilizers for possible future need [IRR: 5.07 (95 %CI: 2.73-9.40)]; and untrusting the physician's decision about tranquilizer prescription [IRR: 1.92 (95 %CI: 1.12-3.30)]. The level of knowledge is marginally associated with tranquilizer misuse.

CONCLUSIONS

There is a strong association between individuals' attitudes towards tranquilizers and the misuse practices of these drugs. Educational interventional studies could help reduce the incidence of tranquilizer misuse.

Increased risk of depression before and after unilateral or bilateral oophorectomy: A self-controlled case series study using a nationwide cohort in South Korea

BACKGROUND

There is insufficient evidence of the association between oophorectomy and depression.

METHODS

A nationwide medical records database of South Korea was used to investigate incidence rate ratios (IRRs) of major depressive disorder before and after oophorectomy (n = 36,284) using a self-controlled case series design. Outcomes before and after hysterectomy (n = 25,415) were identified to compare with those around oophorectomy.

RESULTS

In all oophorectomy and hysterectomy groups, the risk of depression was increased before and after surgery, peaking immediately before or after the operation, with no significant difference in the pattern of the results according to type of surgery. In the bilateral oophorectomy group, the IRR was increased between 2-3 months before the surgery, peaking immediately before surgery at 1.39 (95% CI: 1.30-1.49, p < .0001), and remained heightened for one-year postexposure. Subgroup analyses performed according to ovarian cancer, age group, and hormone replacement therapy produced results similar to those of the main outcome.

LIMITATIONS

Because we used claims data, the detailed clinical information related to oophorectomy is lacking. There is possibility that time-varying confounder besides age and season might have affected the results CONCLUSIONS: The risk of depression increased before and after oophorectomy. The increase in risk of depression started before oophorectomy and peaked immediately before or after the operation, but no significant differences between unilateral and bilateral surgery and cancer and noncancer or among age groups were noted.

Evaluation of disparities in multiple sclerosis risk by age, sex, and nativity in Kuwait:1980-2019

OBJECTIVE

This cross-sectional cohort study quantified the disparities in MS risk by age, sex, nativity from 1980 to 2019 in Kuwait.

METHODS

Age-standardized MS incidence rate (ASIR) (per 100,000 person-years) overall and by subcohorts defined by cross-classification of the period (5-year groups) of diagnosis, age at onset, sex (female or male) and nativity (Kuwaiti or non-Kuwaiti) were computed and analyzed using multivariable negative binomial model.

RESULTS

Overall MS ASIR (per 100,000 person-years) was 3.41 (95% CI: 1.61, 5.21), which exponentially increased from 1980 to 2014 before drifting downward in 2015-2019 period. Compared with adults (age ≥ 40 years), males, non-Kuwaiti residents respectively, young adults (20-39 years), females and Kuwaiti nationals were significantly (p < 0.05) more likely to develop MS after adjusting for the period effect.

CONCLUSIONS

A high overall MS ASIR (per 100,000 person-years) was recorded with substantial temporal variation between 1980 and 2019. Young adults (20-39 years), females and Kuwaiti nationals constituted MS high-risk groups. The knowledge of underlying interface pathways between genetic and environmental factors may provide insights into MS pathogenesis and leads for future research.

Childhood exposure to green space - A novel risk-decreasing mechanism for schizophrenia?

Schizophrenia risk has been linked to urbanization, but the underlying mechanism remains unknown. Green space is hypothesized to positively influence mental health and might mediate risk of schizophrenia by mitigating noise and particle pollution exposure, stress relief, or other unknown mechanisms. The objectives for this study were to determine if green space are associated with schizophrenia risk, and if different measures of green space associate differently with risk. We used satellite data from the Landsat program to quantify green space in a new data set for Denmark at 30×30m resolution for the years 1985-2013. The effect of green space at different ages and within different distances from each person's place of residence on schizophrenia risk was estimated using Cox regression on a very large longitudinal population-based sample of the Danish population (943,027 persons). Living at the lowest amount of green space was associated with a 1.52-fold increased risk of developing schizophrenia compared to persons living at the highest level of green space. This association remained after adjusting for known risk factors for schizophrenia: urbanization, age, sex, and socioeconomic status. The strongest protective association was observed during the earliest childhood years and closest to place of residence. This is the first nationwide population-based study to demonstrate a protective association between green space during childhood and schizophrenia risk; suggesting limited green space as a novel environmental risk factor for schizophrenia. This study supports findings from other studies highlighting positive effects of exposure to natural environments for human health.

Persons with schizophrenia migrate towards urban areas due to the development of their disorder or its prodromata

BACKGROUND

Many studies have identified urban-rural differences in the occurrence of schizophrenia. Though unknown, the underlying causes responsible for these differences have been hypothesized to include urban-rural differences in toxic exposures, diet, infections, stress, or an artifact due to selective migration. Freeman hypothesized that persons with schizophrenia migrate towards larger cities due to development of their disorder or its prodromata. Based on this, the reason for the high frequency of schizophrenia in urban areas is not that those affected have lived in environmentally unfavorable areas, but that people with schizophrenia selectively migrate towards urban areas due to disease onset. No population-based studies accessed the extent and potential impact of this artifact of selective migration.

METHODS

Utilizing a population-based sample of the Danish population, it was investigated if persons with schizophrenia more often migrated towards larger cities due to disease onset. The impact of selective migration on the urban-rural differences was quantified comparing a prospective and a retrospective study.

RESULTS

Compared to healthy controls, persons with schizophrenia spectrum disorder migrate to a higher degree of urbanization due to disease onset (OR=1.18 (1.14-1.23)). However, the bias in urban-rural effect sizes due to this artifact of selective migration was limited.

CONCLUSION

Persons with schizophrenia drift towards urban areas as a consequence of the disorder or its prodromata, but this drift has only limited impact on the urban-rural differences. Therefore, prospective and retrospective studies are both informative on the unknown underlying factor or factors responsible for the urban-rural differences in schizophrenia risk.

Changes in cervical cancer incidence following the introduction of organized screening in Italy

OBJECTIVE

To quantify the impact of organized cervical screening programs (OCSPs) on the incidence of invasive cervical cancer (ICC), comparing rates before and after activation of OCSPs.

METHODS

This population-based investigation, using individual data from cancer registries and OCSPs, included 3557 women diagnosed with ICC at age 25-74years in 1995-2008. The year of full-activation of each OCSP was defined as the year when at least 40% of target women had been invited. Incidence rate ratios (IRRs) with 95% confidence intervals (95% CIs) were calculated as the ratios between age-standardized incidence rates observed in periods after full-activation of OCSPs vs those observed in the preceding quinquennium.

RESULTS

ICC incidence rates diminished with time since OCSPs full-activation: after 6-8years, the IRR was 0.75 (95% CI: 0.67-0.85). The reduction was higher for stages IB-IV (IRR=0.68, 95% CI: 0.58-0.80), squamous cell ICCs (IRR=0.74, 95% CI: 0.64-0.84), and particularly evident among women aged 45-74years. Conversely, incidence rates of micro-invasive (stage IA) ICCs increased, though not significantly, among women aged 25-44years (IRR=1.34, 95% CI: 0.91-1.96). Following full-activation of OCSPs, micro-invasive ICCs were mainly and increasingly diagnosed within OCSPs (up to 72%).

CONCLUSION(S)

Within few years from activation, organized screening positively impacted the already low ICC incidence in Italy and favored down-staging.

Hospital-associated venous thromboembolism in children: incidence and clinical characteristics

OBJECTIVE

To determine incidence and clinical characteristics of hospital-associated venous thromboembolism (VTE) in pediatric patients.

STUDY DESIGN

A retrospective analysis of patients with hospital-associated VTE at the Johns Hopkins Hospital from 1994 to 2009 was performed. Clinical characteristics of patients aged 21 years and younger who developed VTE symptoms after 2 days of hospitalization or <90 days after hospital discharge were examined. International Classification of Diseases, Ninth Revision codes were used to categorize patients with complex chronic medical conditions and trauma.

RESULTS

There were 270 episodes of hospital-associated VTE in 90,485 admissions (rate 30 per 10,000 admissions). Young adults (18-21 years) and adolescents (14-17 years) had significantly increased rates of VTE compared with children (2-9 years) (incidence rate ratio [IRR] 7.7, 95% CI 5.1-12.0; IRR 4.3, 95% CI 2.7-6.8, respectively). A central venous catheter (CVC) was present in 50% of patients, and a surgical procedure was performed in 45% of patients before VTE diagnosis. For patients without a CVC, trauma was the most common admitting diagnosis. CVC-related VTE was diagnosed most frequently in infants (<1 year old) and in patients with malignancy. Renal and cardiac diseases were associated with the highest rates of VTE (51 and 48 per 10,000, respectively). Rates were significantly higher among those with ≥ 4 medical conditions compared with those with 1 medical condition (IRR 4.0, 95% CI 1.4-8.9).

CONCLUSION

Older age and multiple medical conditions were associated with increased rates of hospital-associated VTE. These data can contribute to the design of future clinical trials to prevent hospital-associated VTE in high-risk children.

Association between enhanced access services in pediatric primary care and utilization of emergency departments: a national parent survey

OBJECTIVES

To measure the prevalence of enhanced access services in pediatric primary care and to assess whether enhanced access services are associated with lower emergency department (ED) utilization.

STUDY DESIGN

Internet-based survey of a national sample of parents (n = 820, response rate 41%). We estimated the prevalence of reported enhanced access services and ED use in the prior 12 months. We then used multivariable negative binomial regression to assess associations between enhanced access services and ED use.

RESULTS

The majority of parents reported access to advice by telephone during office hours (80%), same-day sick visits (79%), and advice by telephone outside office hours (54%). Less than one-half of parents reported access to their child's primary care office on weekends (47%), after 5:00 p.m. on any night (23%), or by email (13%). Substantial proportions of parents reported that they did not know if these services were available (7%-56%, depending on service). Office hours after 5:00 p.m. on ≥ 5 nights a week was the only service significantly associated with ED utilization in multivariable analysis (adjusted incidence rate ratio: 0.51 [95% CI 0.28-0.92]).

CONCLUSIONS

The majority of parents report enhanced access to their child's primary care office during office hours, but many parents do not have access or do not know if they have access outside of regular office hours. Extended office hours may be the most effective practice change to reduce ED use. Primary care practices should prioritize the most effective enhanced access services and communicate existing services to families.

Can an airway challenge test predict respiratory diseases? A population-based international study

BACKGROUND

Evidence on the longitudinal association of airway responsiveness with respiratory diseases is scarce. The best indicator of responsiveness is still undetermined.

OBJECTIVE

We investigated the association of airway responsiveness with the incidence of asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis.

METHODS

We studied 3851 subjects who underwent spirometry and methacholine challenge tests both at baseline (1991-1993), when they were 20 to 44 years old, and at follow-up (1999-2002) in the European Community Respiratory Health Survey. Airway responsiveness was defined based on the methacholine dose-response slope on both occasions. Incidence rate ratios for the association of airway responsiveness with disease occurrence were computed by using Poisson regression.

RESULTS

With respect to reference (slope of the fourth quintile or greater), subjects with the greatest degree of airway responsiveness (slope less than the first quintile) showed the greatest risk of developing asthma, COPD, and allergic rhinitis (incidence rate ratios of 10.82, 5.53, and 4.84, respectively; all P < .01). A low slope predicted disease occurrence, even in subjects who did not reach a 20% decrease in FEV1 at the cumulative dose of 1 mg of methacholine (PD20 >1 mg). A decrease in slope over time was an independent predictor of disease risk.

CONCLUSION

Airway responsiveness predicted new-onset asthma, COPD, and allergic rhinitis. Our study supports the use of a continuous noncensored indicator of airway responsiveness, such as the slope of the methacholine dose-response curve, in clinical practice and research because it showed clear advantages over PD20.