Ourania Kolokotroni

A 10-year time-series analysis of respiratory and cardiovascular morbidity in Nicosia, Cyprus: the effect of short-term changes in air pollution and dust storms

BackgroundTo date, a substantial body of research has shown adverse health effects of short-term changes in levels of air pollution. Such associations have not been investigated in smaller size cities in the Eastern Mediterranean. A particular feature in the region is dust blown from the Sahara a few times a year resulting in extreme PM10 concentrations. It is not entirely clear whether such natural phenomena pose the same risks.MethodsThe effect of changes in daily levels of particulate matter (PM10) and ozone (O3) on hospitalization for all, cardiovascular and respiratory causes in the two hospitals in Nicosia during 1 January 1995 and 30 December 2004 was investigated using generalized additive Poisson models after controlling for long- and short-term patterns as well as for the effect of weather. Meteorological records were reviewed to identify dust-storm days and analyses were repeated to quantify their effect on cardio-respiratory morbidity.ResultsFor every 10 μg/m3 increase in daily average PM10 concentrations, there was a 0.9% (95%CI: 0.6%, 1.2%) increase in all-cause and 1.2% (95%CI: -0.0%, 2.4%) increase in cardiovascular admissions. With respect to respiratory causes, an effect was observed only in the warm months. No lagged effects with levels of PM10 were observed. In contrast, positive associations with levels of ozone were only observed the two days prior to admission. These appeared stronger for cardiovascular causes and independent of the effect of PM. All-cause and cardiovascular admissions were 4.8% (95%CI: 0.7%, 9.0%) and 10.4% (95%CI: -4.7%, 27.9%) higher on dust storm days respectively. In both cases the magnitude of effect was comparable to that seen on the quartile of non-storm days with the highest levels of PM10.ConclusionWe observed an increased risk of hospitalization at elevated levels of particulate matter and ozone generally consistent with the magnitude seen across several European cities. We also observed an increased risk of hospitalization on dust storm days, particularly for cardiovascular causes. While inference from these associations is limited due to the small number of dust storm days in the study period, it would appear imperative to issue health warnings for these natural events, particularly directed towards vulnerable population groups.

Asthma and atopy in children born by caesarean section: effect modification by family history of allergies – a population based cross-sectional study

BackgroundStudies on the association of birth by caesarean section (C/S) and allergies have produced conflicting findings. Furthermore, evidence on whether this association may differ in those at risk of atopy is limited. This study aims to investigate the association of mode of delivery with asthma and atopic sensitization and the extent to which any effect is modified by family history of allergies.MethodsAsthma outcomes were assessed cross-sectionally in 2216 children at age 8 on the basis of parents’ responses to the ISAAC questionnaire whilst skin prick tests to eleven aeroallergens were also performed in a subgroup of 746 children. Adjusted odds ratios of asthma and atopy by mode of delivery were estimated in multivariable logistic models while evidence of effect modification was examined by introducing interaction terms in the models.ResultsAfter adjusting for potential confounders, children born by C/S appeared significantly more likely than those born vaginally to report ever wheezing (OR 1.36, 95% CI 1.07-1.71), asthma diagnosis (OR 1.41, 95% CI 1.09-1.83) and be atopic (OR 1.67, 95% CI 1.08-2.60). There was modest evidence that family history of allergies may modify the effect of C/S delivery on atopy (p for effect modification=0.06) but this was not the case for the asthma outcomes. Specifically, while more than a two-fold increase in the odds of being a topic was observed in children with a family history of allergies if born by C/S (OR 2.62, 95% CI 1.38-5.00), no association was observed in children without a family history of allergies (OR 1.16, 95% CI 0.64-2.11).ConclusionsBirth by C/S is associated with asthma and atopic sensitization in childhood. The association of C/S and atopy appears more pronounced in children with family history of allergies.

Prevalence and social environment of cigarette smoking in Cyprus youth

BackgroundTobacco use is the single most preventable cause of morbidity and mortality in humans. Limited data exist regarding the extent of the problem among Cyprus youth. We use the Global Youth Tobacco Survey to assess the prevalence of cigarette smoking among middle and high school students as well as the social environment in which this is taking place.MethodsThe survey was conducted by the Cyprus International Institute for the Environment and Public Health in association with Harvard School of Public Health. A two-stage cluster sample design was used to select a representative sample of students from middle and high schools registered with the Republic of Cyprus in 2005–2006. The study questionnaire consisted of 99 questions and participation in the survey was voluntary. Statistical analyses were performed taking into consideration the specific design of the study and the sample weights associated with each completed questionnaire.ResultsThe prevalence of current smoking, defined as having smoked cigarettes on one or more days of the past 30 days, is 13% among boys and 7% among girls in middle schools, and 36% among boys and 23% among girls in high schools. Furthermore, 16% of middle school students and more than 24% of high school students that had never smoked indicated that they are likely to initiate smoking within the next year. Exposure to environmental tobacco smoke is also very high with 91% of students reporting being exposed to smoke in places outside home. In addition, more than 95% of current smokers reported that they had bought cigarettes in a store during the past month and were not refused cigarettes because of their age.ConclusionSmoking prevalence among Cyprus middle and high school students is high and there are indications of an increase in the prevalence of smoking among girls over the last few years. Susceptibility rates, exposure to second-hand smoke, and access to and availability of cigarettes to youth are also high and concerning. The present survey indicates that the problem of cigarette smoking among youth in Cyprus is significant and requires collective action immediately.

Low serum high-density lipoprotein cholesterol in childhood is associated with adolescent asthma.

Whilst emerging evidence from animal and cell experiments has shown high‐density lipoprotein cholesterol to have anti‐inflammatory effects consistent with a protective role in asthma, human studies investigating the relationship of high‐density lipoprotein cholesterol with asthma have produced conflicting results.

Association of vitamin D with adiposity measures and other determinants in a cross-sectional study of Cypriot adolescents

OBJECTIVE To assess vitamin D status among Cypriot adolescents and investigate potential determinants including BMI and body fat percentage (BF%). DESIGN Participants had cross-sectional assessments of serum vitamin D, physical activity, dietary vitamin D intake and sun exposure. Linear and logistic regression models were used to explore the associations of vitamin D with potential predictors. SETTING Hospitals, Cyprus, November 2007-May 2008. SUBJECTS Adolescents (n 671) aged 16-18 years. RESULTS Mean serum vitamin D was 22·90 (sd 6·41) ng/ml. Only one in ten children had sufficient levels of vitamin D (≥30 ng/ml), while the prevalence of vitamin D deficiency (12-20 ng/ml) and severe deficiency (<12 ng/ml) was 31·7 % and 4·0 %, respectively. Lower vitamin D was associated with winter and spring season, female gender, reduced sun exposure in winter and darker skin. Participants with highest BMI and BF% when compared with a middle reference group had increased adjusted odds of vitamin D insufficiency (OR = 3·00; 95 % CI 1·21, 7·45 and OR = 5·02; 95 % CI 1·80, 13·97, respectively). A similar pattern, although not as strong, was shown for vitamin D deficiency with BF% (OR = 1·81; 95 % CI 1·04, 3·16) and BMI (OR = 1·51; 95 % CI 0·85, 2·67). Participants in the lowest BMI and BF% groups also displayed compromised vitamin D status, suggesting a U-shaped association. CONCLUSIONS Vitamin D deficiency in adolescence is very prevalent in sunny Cyprus, particularly among females, those with darker skin and those with reduced sun exposure in winter. Furthermore, vitamin D status appears to have a U-shaped association with adiposity measures.

Gender differences in objectively assessed physical activity in asthmatic and non‐asthmatic children

To compare objectively assessed physical activity levels, between asthmatic children and non‐asthmatic controls.

Asthma: The Role of Low High-Density-Lipoprotein Cholesterol in Childhood and Adolescence

Background: Several studies have examined the relationship of asthma with serum dyslipidemia and reported positive, negative or no association. Most studies were limited by their cross-sectional design and the wide age range of the participants. In a cohort of children in Cyprus, we explored the association of asthma with serum high-density-lipoprotein cholesterol (HDL-C) at age 16-18 years (follow-up) independently of and in relation to HDL-C at age 11-12 years (baseline). Methods: In a case-control design, we recruited active asthmatics (AA; n = 68), current wheezers only (CWO; n = 123) and non-asthmatic controls (n = 660). Logistic regression models were used to evaluate associations of asthma with follow-up serum HDL-C and the role of baseline HDL-C. Results: At follow-up, mean HDL-C levels in AA and CWO patients were significantly lower than in the controls (47.9 and 49.7 vs. 53.4 mg/dl; p = 0.001 and p = 0.011). We observed significant associations of AA patients with low HDL-C (<15th percentile; OR 2.32, 95% CI 1.16-4.47) that remained significant after further adjustment for baseline HDL-C (OR 2.14, 95% CI 1.06-4.14). Stratification by baseline HDL-C indicated that the association was significant only in those with high baseline HDL-C (OR 2.40, 95% CI 1.03-5.20). Stratification by IgE sensitization showed that the association was pronounced only in subjects who were sensitized (OR 3.41, 95% CI 1.12-9.88). Conclusions: Adolescent asthma is associated with low serum HDL-C independent of previous HDL-C levels in childhood. The association appears pronounced in those with a drop in HDL-C levels between childhood and adolescence and in those who have IgE sensitization. i 2014 S. Karger AG, Basel

High cardiorespiratory fitness is inversely associated with incidence of overweight in adolescence: A longitudinal study

To assess the association of baseline cardiorespiratory fitness (CRF) with incidence of overweight over a 4.6‐year period in adolescence. In a cohort of 4878 adolescents, we assessed body mass index in years 2001–2003 and 2007. CRF was assessed at baseline as maximal oxygen consumption (VO2max, mL/kg/min) using the 20‐m shuttle run test and was examined against incidence of overweight at follow‐up. Estimated VO2max at baseline was higher in males than in females, P < 0.001, and was lower in overweight and obese than in non‐overweight subjects. The incidence of overweight at follow‐up among non‐overweight participants at baseline was 15.5% [95% confidence interval (CI) 13.7% to 17.3%] in males and 5.6% (95% CI 4.9% to 7.0%) in females, P < 0.001. Adjusted odds ratio for incidence of overweight in participants in the fourth quartile of VO2max was 0.40 (95%CI 0.26 to 0.61) in males and 0.57 (95% CI 0.33 to 0.99) in females in comparison with participants in the first quartiles of VO2max. Incidence of overweight was three times more frequent in males than in females. Among non‐overweight at baseline, high fitness levels were inversely associated with incidence of overweight at follow‐up, suggesting that interventions aiming to increase CRF in early childhood might help reverse increasing trends in obesity.

Associations of body fat percent and body mass index with childhood asthma by age and gender

High body mass index (BMI) has been shown to be associated with asthma, but the pattern of this association is still unclear and may differ by gender or stage of puberty. BMI is only a proxy of adiposity, whereas estimation of body fat percent (BF%) by the bioimpedance technique is considered an accurate measure of adiposity. We investigated whether BMI and BF% behave differently in their association with asthma between genders, before and during adolescence.

Association of Serum Vitamin D with Asthma and Atopy in Childhood: Review of Epidemiological Observational Studies

During the last decades, vitamin D deficiency has re-emerged worldwide affecting not only populations bone health, but also several other conditions including asthma and allergies. Increasing number of published epidemiological studies in the last seven years have examined the role of vitamin D deficiency in childhood in several outcomes including asthma diagnosis, asthma disease severity, allergic sensitization and atopy. This review presents evidence on this association from a systematic search in the literature of all available observational studies and their limitations. A total of 33 studies were identified: 3 prospective, 16 case-control and 14 cross-sectional studies. Overall, most of the case-control studies tend to report that asthmatics have lower vitamin D levels/status as compared to healthy children, although most of these studies are mainly descriptive in nature and tend to provide only crude, unadjusted comparisons. Studies that investigated the association of vitamin D with the prevalence, development and/or severity of asthma gave mixed findings, with the exception of studies that focused on vitamin D and severity of asthma which suggest a positive association of vitamin D levels with better asthma control, reduced use of asthma medication, fewer asthma exacerbations and lower utilisation of health care facilities for urgent treatment. Insufficient evidence also exists for the association of inadequate vitamin D status with higher risk of atopic sensitization. The lack of adequate number of prospective studies, the variable definitions for case ascertainment, the wide age range of the participants, and commonly the inadequate control for confounders make inferences difficult. Future studies are needed with a prospective design and repeated measurements of vitamin D to provide critical information on the timing and dosage of future vitamin D supplementation interventions.