Prevalence and Risk Factors for Chronic Obstructive Pulmonary Disease According to Symptoms and Spirometry

Figures & data

Table 1.  Comparison Between the City (Pelotas) and the Whole Country (Brazil) According to Demographic, Socioeconomic and Health‐Related Variables. Pelotas, 2001

Variable	Pelotas	Brazil
Sex (including all ages)
Men	48.8%	49.2%
Women	51.2%	50.8%
Mean monthly income (head of the family)	US$ 44.9	US$ 43.0
Gini index (income inequality)	0.60	0.64
Schooling (years)
0–3	27.7%	41.1%
4–10	55.8%	45.1%
≥ 11	16.5%	13.8%
Infant mortality rate	20/1,000	29/1,000

*Sources: Brazilian Institute of Geography and Statistics (sex, monthly income, Gini index, and schooling), and local/national surveys (infant mortality rate).

Table 2.  Definitions of Chronic Obstructive Pulmonary Disease (COPD) According to Symptoms and/or Spirometry. Pelotas, 2001

Criteria (Abbreviation)	Definition
Symptoms of chronic bronchitis	Presence of chronic symptoms (cough with phlegm on most of the days during three months of the year, for at least two consecutive years) regardless of spirometry results
COPD GOLD Stage 0 (GOLD stage 0)	Presence of chronic symptoms (cough with phlegm on most of the days during three months of the year, for at least two consecutive years) and FEV1/FVC ≥ 70%
COPD GOLD Stage II (GOLD stage II)	FEV1/FVC < 70% and FEV1 50–80% predicted
COPD Fixed Ratio** (FR)	FEV1/FVC < 70%
COPD ERS*** (ERS)	FEV1/FVC < 88% predicted (males) and FEV1/FVC < 89% predicted (females)

*In accordance with the Global Obstructive Lung Disease (GOLD) guidelines [[26]].

**From Ref. [[15]].

***In accordance with the European Respiratory Society (ERS) guidelines.

Table 3.  Description of the Total Sample (n = 1,047) and the Sub‐sample with Spirometry (n = 191) in Terms of the Presence of Clinical Symptoms and Demographic, Socioeconomic and Behavioral Variables. Brazil, 2001

Variables	Percentage of sample (95% CI)
	Total sample (n = 1,046)	Spirometry sample (n = 191)
Sex
Females	59.1% (56.1–62.1)	61.8% (54.9–68.7)
Males	40.9% (37.9–43.9)	38.2% (31.3–45.1)
Age (years)
40–49	42.4% (39.4–45.4)	47.6% (40.5–54.7)
50–59	35.4% (33.0–38.3)	34.0% (27.3–40.7)
60–69	21.9 (19.4–24.4)	18.3% (12.8–23.8)
Skin colour
White	84.2% (82.0–86.4)	83.8% (78.6–89.0)
Non‐white	15.8% (13.6–18.0)	16.2% (11.0–21.4)
Family income (minimum wages**)
< 1.01	28.1% (25.4–30.8)	29.3% (22.8–35.6)
1.01–3.00	42.7% (39.7–45.7)	43.5% (36.5–50.5)
3.01–6.00	15.7% (13.5–17.9)	15.2% (10.1–20.3)
6.01–10.00	7.2% (5.6–8.8)	8.4% (4.5–12.3)
>10.00	5.4% (4.0–6.8)	3.7% (1.0–6.4)
Schooling (years of formal education)
0	7.4% (5.8–9.0)	7.9% (4.1–11.7)
1–4	28.5% (25.8–31.2)	24.1% (18.0–30.2)
5–8	31.7% (28.9–34.5)	35.1% (28.3–41.9)
≥ 9	32.4% (29.6–35.2)	33.0% (26.3–39.7)
Smoking status (cig/day)
Non‐smokers	43.4% (40.4–46.4)	42.9% (35.9–49.9)
Ex‐smokers	27.2% (24.5–29.9)	25.1% (18.9–31.2)
Smokers
< 20	14.0% (11.9–16.1)	15.2% (10.1–20.3)
≥ 20	15.4% (13.2–17.6)	16.8% (11.5–22.1)
Symptoms of Chronic Bronchitis
No	92.2% (90.6–93.8)	89.5% (85.23–93.8)
Yes	7.8% (6.2–9.4)	10.5% (6.2–14.8)

*9 missing values.

**The value of one minimum wage in 2001 was equivalent to US$ 80 nowadays.

Table 4.  Prevalence of Chronic Obstructive Pulmonary Disease According to Different Criteria Stratified by Sex, Age, Schooling Level and Smoking Status. Brazil, 2001

Variables	Symptoms of chronic bronchitis	COPD GOLD Stage 0	COPD Fixed ratio	COPD GOLD Stage II	COPD ERS
Sex	p = 0.08	p = 0.35	p = 0.04	p = 0.06	p = 0.77
Men	9.6%	8.2%	21.9%	15.1%	26.0%
Women	6.6%	6.6%	11.0%	6.8%	28.0%
Age (years)	p = 0.01**	p = 0.02**	p = 0.01**	p = 0.04**	p = 0.07**
40–49	5.9%	5.9%	7.7%	4.4%	27.5%
50–59	7.4%	6.4%	21.5%	15.4%	24.6%
60–69	12.3%	11.4%	22.9%	14.3%	31.4%
Schooling (years of formal education)	p < 0.001**	p < 0.001**	p = 0.05**	p = 0.01**	p = 0.07**
0	16.9%	15.6%	26.7%	20.0%	33.3%
1–4	11.4%	10.7%	21.7%	15.2%	37.0%
5–8	5.7%	5.1%	11.9%	10.4%	25.4%
≥ 9	4.7%	4.4%	11.1%	3.2%	20.6%
Smoking status	p < 0.001	p < 0.001	p = 0.009	p < 0.001	p < 0.001
Non‐smokers	3.1%	3.1%	6.1%	1.2%	11.0%
Ex‐smokers	7.4%	6.0%	31.3%	25.0%	47.9%
Current smokers	15.3%	14.7%	14.8%	9.8%	32.8%
Overall	7.8%	7.3%	15.2%	9.9%	27.2%

*Chi‐square test for heterogeneity.

**Chi‐square test for trend.

Figure 1. Relationship between the spirometric results (Venn's diagram). Pelotas, 2001. FR: Fixed Ratio Criteria, ERS: European Respiratory Society Criteria, GOLD II: Global Obstructive Lung Disease Criteria (Stage II). [From Ref. [[26]].]

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. Global Initiative for Chronic Obstructive Lung Disease, World Health Organization, National Heart, Lung, and Blood Institute, Bethesda, MD 2001, Available at: URL: http://www.goldcopd.com/

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