G. Verlato

The Verona diabetes study: a population-based survey on known diabetes mellitus prevalence and 5-year all-cause mortality

SummaryThis population-based survey aimed to determine the prevalence of known diabetes mellitus on 31 December 1986, and to assess all-cause mortality in the subsequent 5 years (1987–1991) in Verona, Italy. In the study of prevalence, 5996 patients were identified by three independent sources: family physicians, diabetes clinics, and drug prescriptions for diabetes. Mortality was assessed by matching all death certificates of Verona in 1987–1991 with the diabetic cohort. Overall diabetes prevalence was 2.61% (95% confidence interval 2.56–2.67). Prevalence of insulin-dependent and non-insulin-dependent diabetes mellitus was 0.069% (0.059–0.078) and 2.49% (2.43–2.54), respectively. Diabetes prevalence sharply increased after age 35 years up to age 75–79, and finally declined. Prevalence was higher in men up to age 69 years, in women after age 75 years. Of the diabetic cohort 1260 patients (592 men, 668 women) died by 31 December 1991, yielding an overall standardized mortality ratio of 1.46 (CI 1.38–1.54). Even though the differences narrowed with age, mortality rates in the diabetic cohort were higher than in the non-diabetic population at all ages. Women aged 65–74 years showed observed/expected ratio higher than men (2.27, CI 1.92–2.66, vs 1.50, CI 1.30–1.72), while in other age groups the sex-related differences were not significant. Pharmacological treatment of diabetes was associated with an excess mortality, while treatment with diet alone showed an apparent protective effect on mortality (observed/expected ratio 0.73, CI 0.58–0.92). In conclusion, in Verona diabetes has a prevalence similar to that of other European countries, and is associated with an excess mortality which is observed in both sexes, at all ages, and with any anti-diabetic pharmacologic treatment. Diet-treated diabetes seems to be associated with a significant reduction in the mortality risk.

Trends in the prevalence of asthma and allergic rhinitis in Italy between 1991 and 2010

The prevalence of asthma increased worldwide until the 1990s, but since then there has been no clear temporal pattern. The present study aimed to assess time trends in the prevalence of current asthma, asthma-like symptoms and allergic rhinitis in Italian adults from 1990 to 2010. The same screening questionnaire was administered by mail or phone to random samples of the general population (age 20–44 yrs) in Italy, in the frame of three multicentre studies: the European Community Respiratory Health Survey (ECRHS) (1991–1993; n=6,031); the Italian Study on Asthma in Young Adults (ISAYA) (1998–2000; n=18,873); and the Gene Environment Interactions in Respiratory Diseases (GEIRD) study (2007–2010; n=10,494). Time trends in prevalence were estimated using Poisson regression models in the centres that repeated the survey at different points in time. From 1991 to 2010, the median prevalence of current asthma, wheezing and allergic rhinitis increased from 4.1% to 6.6%, from 10.1% to 13.9% and from 16.8% to 25.8%, respectively. The prevalence of current asthma was stable during the 1990s and increased (relative risk 1.38, 95% CI 1.19–1.59) from 1998–2000 to 2007–2010, mainly in subjects who did not report allergic rhinitis. The prevalence of allergic rhinitis has increased continuously since 1991. The asthma epidemic is not over in Italy. During the past 20 yrs, asthma prevalence has increased by 38%, in parallel with a similar increase in asthma-like symptoms and allergic rhinitis.

Long-term Instability of Fasting Plasma Glucose, a Novel Predictor of Cardiovascular Mortality in Elderly Patients With Non–Insulin-Dependent Diabetes Mellitus The Verona Diabetes Study

BACKGROUND We recently reported that long-term fasting plasma glucose (FPG) instability predicts all-cause mortality in elderly patients with non-insulin-dependent diabetes mellitus (NIDDM). The aim of the present study was to evaluate whether glucose instability, as represented by the coefficient of variation of FPG concentrations (CV-FPG) measured during a 3-year period, can predict specific causes of death in the subsequent 5 years. METHODS AND RESULTS Five hundred sixty-six elderly patients with NIDDM were followed up for 5 years to assess mortality and causes of death. All FPG determinations of the 3 years preceding the follow-up available in the clinical records were collected and analyzed. Patients were grouped in tertiles of mean FPG, CV-FPG, and the slope of FPG. These parameters of glucose control, as well as sex, age, duration of diabetes, insulin treatment, cigarette smoking, hypertension, and total cholesterol, were included in a multivariate analysis of mortality. During the follow-up, 63 men and 128 women died. Diabetes- and malignancy-related mortality were not independently associated with any parameter of glucose control, whereas cardiovascular-related mortality was independently associated with CV-FPG (P=.007) but not with the mean or the slope of FPG. In particular, the relative risk of cardiovascular mortality in subjects in tertile III versus tertile I of CV-FPG was 2.40 (95% CI, 1.28 to 4.53). CONCLUSIONS These results indicate that FPG instability is a predictor of cardiovascular-related mortality in elderly patients with NIDDM and suggest that glucose stability might be a goal in the management of these patients.

Variations in the prevalence across countries of chronic bronchitis and smoking habits in young adults

The present work aims to assess the international variation in the prevalence of chronic bronchitis and its main risk factor, smoking habits, in young adults of 35 centres from 16 countries. Respiratory symptoms and pulmonary function were assessed in 17,966 subjects (20-44 yrs), randomly selected from the general population, in the frame of the European Community Respiratory Health Survey. The median prevalence of chronic bronchitis was 2.6%, with wide variations across countries (p<0.001; 0.7-9.7%). The prevalence of current smokers ranged 20.1-56.9%, (p<0.001) with a median value of 40%. Current smoking was the major risk factor for chronic bronchitis, especially in males. Its effect increased according to number of pack-yrs: in males, the odds ratio of chronic bronchitis was 3.51 (95% confidence interval (CI) 2.31-5.32) in 1-14 pack-yrs smokers and increased to 17.32 (9.97-30.11) in > or = 45 pack-yrs smokers with respect to nonsmokers. Only 30% of the geographical variability in prevalence could be explained by differences in smoking habits, suggesting that other environmental and/or genetic factors may play an important role. In conclusion, chronic bronchitis is a substantial health problem even in young adults. The impressive prevalence in current smokers in most countries highlights the need to improve the quality of prevention.

Nonresponse bias in EC Respiratory Health Survey in Italy

In the three Italian centres involved in the European Community Respiratory Health Survey (ECRHS), prevalence of asthma-like symptoms was assessed through a mailback questionnaire. Since the nonresponse rate was not negligible, ranging 10-18%, we investigated whether nonresponse bias affected the results and, if so, whether the bias could be eliminated from the final estimates of prevalence. A screening questionnaire was sent by mail to 7,000 randomly selected subjects 20-44 yrs of age, and nonresponders were contacted again by phone. Additional information was collected on a subsample of the respondents through a clinical interview. A logistic regression analysis showed that, except for one symptom (awakening for coughing), symptom prevalence significantly decreased from the first to the subsequent contact, when controlling for age, sex, centre and season of interview. The decrease in symptom prevalence was largely independent of smoking habits and socioeconomic status, and was seemingly caused by a symptom-related self-selection. When correcting results according to a linear regression model, observed estimates appeared to be slightly overestimated, by 4-10%. A simulation with the Italian data showed that the bias increased steeply at nonresponse rate higher than 30%, a situation quite common in asthma surveys. In conclusion, nonresponse bias affects the results of ECRHS in Italy, slightly inflating prevalence estimates. To make reliable comparisons on international data in the presence of different nonresponse rates, a correction of the observed prevalence seems necessary.

The role of climate on the geographic variability of asthma, allergic rhinitis and respiratory symptoms: results from the Italian study of asthma in young adults

Background:  Variations in the prevalence of respiratory symptoms according to geo‐climatic factors could provide important clues to the knowledge of the aetiology of asthma.

Eczema, atopy and allergen exposure in adults: a population‐based study

Background There are few published studies on geographical variation in prevalence of eczema in adults or its association with recognised risk factors for allergic disease.

Long-term instability of fasting plasma glucose predicts mortality in elderly NIDDM patients: the Verona Diabetes Study

SummaryThe aim of this study was to evaluate whether long-term glucose control, as assessed by fasting plasma glucose determinations during 3 years, is a predictor of all-cause mortality in elderly NIDDM patients. Five hundred and sixty-six NIDDM patients attending the Verona Diabetes Clinic, aged 75 years and over, were followed-up from 1 January 1987 to 31 December 1991 to assess all-cause mortality. From their clinical records all fasting plasma glucose determinations available for the years 1984 to 1986 were collected and analysed. Patients were grouped in tertiles according to mean (M-FPG), coefficient of variation (CV-FPG) and trend over time (slope, S-FPG) of fasting plasma glucose during the period of retrospective evaluation. Mortality was assessed by observed/expected ratios, univariate Kaplan-Meier survival analysis and multivariate Poisson regression model. By 31 December 1991, 61 men and 127 women had died. Increased observed/expected ratios were found in women from the top M-FPG tertile, in patients (men and women) from the top CV-FPG tertile and in patients with a S-FPG less than −0.30 mmol/l per year (lowest tertile). Patients in the lowest tertile of CV-FPG and in the middle tertile of S-FPG had a reduced mortality risk. Kaplan-Meier survival analysis indicated that patients with high CV-FPG as well as those in tertiles I and III of S-FPG (i.e., those with a definitely negative or definitely positive slope) had an increased probability of dying, without any significant differences between the three tertiles of M-FPG. Poisson regression model showed that CV-FPG, but not M-FPG or S-FPG, was an independent significant predictor of mortality. These results suggest that glucose stability needs to be considered along with the absolute level of metabolic control when treating elderly NIDDM patients.

The Gene-Environment Interactions in Respiratory Diseases (GEIRD) project.

The role of genetic and environmental factors, as well as their interaction, in the natural history of asthma, allergic rhinitis and chronic obstructive pulmonary disease (COPD) is largely unknown. This is mainly due to the lack of large-scale analytical epidemiological/genetic studies aimed at investigating these 3 respiratory conditions simultaneously. The GEIRD project is a collaborative initiative designed to collect information on biomarkers of inflammation and oxidative stress, individual and ecological exposures, diet, early-life factors, smoking habits, genetic traits and medication use in large and accurately defined series of asthma, allergic rhinitis and COPD phenotypes. It is a population-based multicase-control design, where cases and controls are identified through a 2-stage screening process (postal questionnaire and clinical examination) in pre-existing cohorts or new samples of subjects. It is aimed at elucidating the role that modifiable and genetic factors play in the occurrence, persistence, severity and control of inflammatory airway diseases, by way of the establishment of a historical multicentre standardized databank of phenotypes, contributed by and openly available to international epidemiologists. Researchers conducting population-based surveys with standardized methods may contribute to the public-domain case-control database, and use the resulting increased power to answer their own scientific questions.

Geographical variation and the determinants of domestic endotoxin levels in mattress dust in Europe

UNLABELLED Endotoxin exposures have manifold effects on human health. The geographical variation and determinants of domestic endotoxin levels in Europe have not yet been extensively described. To investigate the geographical variation and determinants of domestic endotoxin concentrations in mattress dust in Europe using data collected in the European Community Respiratory Health Survey follow-up (ECRHS II). Endotoxin levels were measured in mattress dust from 974 ECRHS II participants from 22 study centers using an immunoassay. Information on demographic, lifestyle, and housing characteristics of the participants was obtained in face-to-face interviews. The median endotoxin concentration in mattress dust ranged from 772 endotoxin units per gram (EU/g) dust in Reykjavik, Iceland, to 4806 EU/g in Turin, Italy. High average outdoor summer temperature of study center, cat or dog keeping, a high household crowding index, and visible damp patches in the bedroom were significantly associated with a higher endotoxin concentrations in mattress dust. There is a large variability in domestic endotoxin levels across Europe. Average outdoor summer temperature of study center, which explains only 10% of the variation in domestic endotoxin level by center, is the strongest meteorological determinant. The observed variation needs to be taken into account when evaluating the health effects of endotoxin exposures in international contexts. PRACTICAL IMPLICATIONS The incoherent observations of the health effects of endotoxin may be partly owing to the geographical heterogeneity of endotoxin exposure. Therefore, the observed variation should be considered in further studies. Measurements of indoor endotoxin are recommended as an indicator for the level of exposures of individual domestic environments.