Environmental tobacco smoke exposure at home and smoking prevalence in the general Portuguese population--the INAsma study.

BACKGROUND: We aimed to: 1) estimate the prevalence of exposure to environmental tobacco smoke (ETS) at home in the Portuguese population; 2) estimate tobacco smoking prevalence in Portugal; 3) identify social and personal characteristics associated with smoking or exposure to ETS. METHODS: Nationwide, cross-sectional, population-based telephone survey. Overall, 6003 individuals completed the interview. ETS exposure at home was defined as exposure to at least one current smoker at home. A smoker was defined as someone with 15 years or older, smoking at least 1 cigarette per day during a year; a current smoker (CS) smoked in the last month. RESULTS: Exposure to ETS at home was reported by 26.6% (95%CI 25.5-27.7) of the participants. Living in households with ≥4 persons (OR=2.31; 95%CI[1.81-2.96]), being a current smoker (OR=7.29; 95%CI[5.74-9.26]) or having current asthma (OR=2.06; 95%CI[1.45-2.94]) were factors positively associated with ETS exposure. When analyzed by gender, the effect of current asthma was only relevant to females. Currently 19.0% (95%CI 18.0-20.0) of the Portuguese population smokes tobacco and 17.2% (95%CI 16.2-18.2) are ex-smokers. CS prevalence is higher in males than females (26.5%versus 12.2%, p<0,001). The odds of being a CS were higher for males, the more educated, and those exposed to ETS at home. When analyzed by gender, school education only affected females. CONCLUSION: Exposure to ETS at home was higher than previously reported. Children/adolescents and asthma patients may have a higher risk of exposure. This report endorses a decreasing trend in the prevalence of tobacco smoking in Portuguese males, but a tendency to increase in females.

On the role of subtype selective adenosine receptor agonists during proliferation and osteogenic differentiation of human primary bone marrow stromal cells.

Purines are important modulators of bone cell biology. ATP is metabolized into adenosine by human primary osteoblast cells (HPOC); due to very low activity of adenosine deaminase, the nucleoside is the end product of the ecto-nucleotidase cascade. We, therefore, investigated the expression and function of adenosine receptor subtypes (A(1) , A(2A) , A(2B) , and A(3) ) during proliferation and osteogenic differentiation of HPOC. Adenosine A(1) (CPA), A(2A) (CGS21680C), A(2B) (NECA), and A(3) (2-Cl-IB-MECA) receptor agonists concentration-dependently increased HPOC proliferation. Agonist-induced HPOC proliferation was prevented by their selective antagonists, DPCPX, SCH442416, PSB603, and MRS1191. CPA and NECA facilitated osteogenic differentiation measured by increases in alkaline phosphatase (ALP) activity. This contrasts with the effect of CGS21680C which delayed HPOC differentiation; 2-Cl-IB-MECA was devoid of effect. Blockade of the A(2B) receptor with PSB603 prevented osteogenic differentiation by NECA. In the presence of the A(1) antagonist, DPCPX, CPA reduced ALP activity at 21 and 28 days in culture. At the same time points, blockade of A(2A) receptors with SCH442416 transformed the inhibitory effect of CGS21680C into facilitation. Inhibition of adenosine uptake with dipyridamole caused a net increase in osteogenic differentiation. The presence of all subtypes of adenosine receptors on HPOC was confirmed by immunocytochemistry. Data show that adenosine is an important regulator of osteogenic cell differentiation through the activation of subtype-specific receptors. The most abundant A(2B) receptor seems to have a consistent role in cell differentiation, which may be balanced through the relative strengths of A(1) or A(2A) receptors determining whether osteoblasts are driven into proliferation or differentiation.