Figures
- FIGURE 1
Forest plot for the effect of wealth score on forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC), adjusted for age, sex and all other confounders (body mass index, education, smoking, passive smoking, exposure to a dusty job, family history of breathing problems, childhood hospitalisation for breathing problems and previous diagnosis of tuberculosis). The coefficient gives the mean change in FEV1/FVC (%) for a one-unit increase in the wealth score in each of the sites.
- FIGURE 2
Forest plot showing the association between the odds of having forced expiratory volume in 1 s/forced vital capacity below the lower limit of normal (based on The National Health and Nutrition Examination Survey (NHANES) equations) and wealth score. The odds ratios show the effect of a one-unit increase in the wealth score on the odds of obstruction in each of the sites, adjusted for body mass index, education, smoking, passive smoking, working in a dusty job, family history of chronic obstructive pulmonary disease, hospitalisation as a child for breathing problems and tuberculosis.
- FIGURE 3
Association between site-level means of wealth score and a) mean forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) (%), b) proportion of subjects with obstruction (FEV1/FVC<lower limit of normal). The dashed lines show the linear regression lines of best fit weighted to allow for the number of subjects included in each site.
Tables
- TABLE 1
Characteristics of the study population in the 12 centres#
Sousse, Tunisia Kashmir, India Ife, Nigeria Fes, Morocco Tirana, Albania Annaba, Algeria Penang, Malaysia Riyadh, S. Arabia Blantyre, Malawi Sri Lanka Naryn, Kyrgyzstan Chui, Kyrgyzstan Subjects n¶ 798 1077 1683 974 1188 938 1200 843 758 1408 1160 1876 Participants n (%)+ 660 (83) 738 (69) 864 (51) 760 (78) 928 (78) 862 (92) 649 (54) 679 (81) 402 (53) 1035 (74) 820 (71) 858 (46) Males 51 52 54 52 49 50 49 52 54 48 48 42 Age years 52±9 52±10 53±11 55±12 56±12 54±11 55±10 51±8 51±9 53±9 52±10 53±10 BMI ≥25 76 23 44 66 73 69 55 88 40 45 62 65 Height cm 164±9 160±9 165±8 162±9 164±9 164±10 159±8 162±9 163±8 157±9 162±9 163±9 Smoking pack years§ 16±25 133±207 1±6 8±19 12±19 11±19 6±16 9±24 2±26 3±9 6±12 10±18 Passive smokingƒ 35 64 2 12 38 11 26 6 3 8 3 11 Dusty job## 50 1 38 44 64 28 32 17 26 36 6 34 Tuberculosis¶¶ 0 0 1 1 1 2 0 2 5 1 1 1 Family history of COPD++ 6 2 0 10 8 6 5 3 20 3 2 7 Childhood hospitalisation§§ 3 0 1 1 1 2 3 1 1 3 1 7 Post primary educationƒƒ 50 18 59 28 80 56 65 65 46 73 94 97 FEV1/FVC % 80±7 77±10 79±8 79±8 78±10 78±7 81±7 83±6 79±8 80±9 78±7 76±9 FEV1/FVC<LLN 5 16 7 9 9 7 3 3 7 8 8 13 Wealth score### 9±1 4±2 5±2 8±2 9±2 8±1 9±1 10±0 4±3 6±2 5±1 6±2 GNI per capita US$ PPP 9680 4750 4930 6160 9950 12 860 22 530 53 760 750 9480 3100 3100 Asthma ever 8 2 1 7 6 8 4 31 5 6 2 3 Open fire >20 years¶¶¶ 23 100 27 22 91 18 26 17 51 44 88 55 Smoker+++ 45 53 14 30 37 39 25 26 17 24 31 38 Data are presented as mean±sd or %, unless otherwise stated. BMI: body mass index; COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; LLN: lower limit of normal; GNI: gross national income; PPP: purchasing power parity. #: individual responses have been weighted according to the probability of selection to provide population estimates of means and percentages for each of the study areas; ¶: individuals selected for possible inclusion in the Burden of Obstructive Lung Disease (BOLD) study using a random sampling process; +: individuals included in the study (i.e. those who agreed to take part in the BOLD study and provided useable data from both the questionnaire and spirometry tests); §: 1 pack-year equals an average of 20 cigarettes per day for 1 year or the equivalent amount of other types of tobacco smoking; ƒ: somebody else in the household smoked during the past 2 weeks; ##: the respondent was employed in a dusty job for at least 1 year; ¶¶: ever diagnosed with tuberculosis; ++: a close sibling or parent had been diagnosed as having emphysema, chronic bronchitis or COPD by a health professional; §§: hospitalised for breathing problems before the age of 10 years; ƒƒ: highest level of education completed was above primary school; ###: calculated from ownership of a range of assets (see methods and [12]); ¶¶¶: exposure to open fires for cooking and/or heating for more than 20 years; +++: current or ex-smoker.
- TABLE 2
Associations between forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) % and wealth score, adjusted for age and sex only and then for multiple potential confounding factors
Adjusted for age and sex only Adjusted for age, sex and other potential confounders Coefficient 95% CI p-value Coefficient 95% CI p-value Wealth Score 0.36 0.22–0.49 <0.001 0.23 0.11–0.34 <0.001 Females 2.43 1.63–3.24 <0.001 0.76 0.01–1.50 0.046 Age years −0.27 −0.31– −0.23 <0.001 −0.25 −0.29– −0.22 <0.001 BMI <18.5 −0.85 −2.64–0.94 0.351 ≥18.5–<25 0 ≥25–≤30 0.85 0.50–1.19 <0.001 >30 1.23 0.68–1.77 <0.001 Education level completed −0.10 −0.32–0.12 0.383 Smoking pack-years −0.06 −0.09– −0.04 <0.001 Passive smoking −0.31 −1.14–0.53 0.474 Worked in a dusty job years −0.04 −0.06– −0.01 0.003 Family history of COPD −0.75 −1.87–0.37 0.191 Hospitalised as a child −2.44 −5.18–0.29 0.080 Tuberculosis −2.30 −4.40– −0.19 0.032 Coefficients indicate the effect of an individual having the stated characteristic (versus not having that characteristic) on FEV1/FVC % or for a one-unit increase in that variable, adjusted for all other variables in that column (e.g. individuals with a history of tuberculosis had an FEV1/FVC 2.3% lower on average than comparable individuals without a history of tuberculosis. Bold denotes statistical significance. COPD: chronic obstructive pulmonary disease.
Supplementary Material
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Table S1. Sensitivity analysis ERJ-01880-2016_Table_S1
