High prevalence of emphysema and its association with BMI: A study of smokers with normal spirometry

Figures & data

Table I.  Data showing the two groups of non-COPD individuals regarding gender, mean age, BMI, smoking history. and number of pack-years.

Characteristics	Lower normal values of lung function (n = 18)	Higher normal values of lung function (n = 36)
Female (%)	28	39
Age (years)	53.2 (4.1)	52.1 (4.3)
BMI (kg/m^2)	26.7 (4.0)	25.8 (3.5)
Smoking (years)	32.0 (7.8)	35.1 (5.7)
Pack-years	25.0 (11.7)	28.7 (11.9)

Notes: None of the differences was statistically significant. Data are presented as mean and standard deviation (±SD); n = number of subjects; BMI = body mass index; pack-years = number of years of smoking x average number of cigarettes smoked per day, divided by 20.

Table II.  Findings of emphysema on HRCT in the group of smokers with lower normal values of lung function and the group with higher normal values of lung function: Grade and type of emphysema.

	Lower normal values of lung function (n = 18)	Higher normal values of lung function (n = 36)
Emphysema	8 (44%)	15 (42%)
Grade of emphysema
0	10	21
3	3	7
4	5	7
5	0	1
Type of emphysema
>CLE	6	4
CLE = PSE	1	2
>PSE	1	9

Notes: None of the differences was statistically significant. >CLE: centrilobular emphysema alone or predominant; >PSE: paraseptal emphysema alone or predominant; CLE = PSE: centrilobular emphysema = paraseptal emphysema.

Table III.  Subjects allocated according to findings on HRCT. Data showing mean age, gender, number of pack-years, BMI, and lung function values.

	Emphysema on HRCT (n = 23)	No emphysema on HRCT (n = 31)
Female,%	43	39
Age (years)	52.7 (50.8–54.4)	52.3 (50.7–53.8)
BMI (kg/m^2)	24.2 (22.8–25.7)	27.4 (26.2–28.6)
Smoking (years)	34.2 (31.6–36.8)	34.0 (31.4–36.6)
Pack-years	29.4 (24.7–34.0)	26.0 (21.4–30.6)
FEV1 (% pred.)	103 (96–110)	103 (97–109)
FEF25 (% pred.)	104 (93–115)	106 (95–117)
FEF50 (% pred.)	76 (64–88)	78 (68–89)
FEF75 (% pred.)	52 (43–62)	56 (47–65)
FVC (% pred.)	110 (104–116)	109 (104–115)
FEV1/FVC ratio (%)	77 (74–79)	77 (75–79)
FEV1/FVC ratio (% pred.)	98 (96–101)	99 (97–101)
Rev-B2 (%)	3.5 (1.7–5.4)	4.2 (2.6–5.8)
HRCT, –950 HU (%)	1.096 (0.34–1.84)	0.665 (0.221–1.108)
CRP (mg/l)	2.05 (1.13–2.97)	3.43 (1.50–5.35)
Eosinophils (%)	0.186 (0.117–0.254)	0.145 (0.107–0.182)

Notes: There were no significant differences except for BMI. Data are presented as mean and standard deviation (SD);% pred = percentage of predicted; Rev-B2 = reversibility test with beta-2 agonist. T-tests were used for all variables and CRP and eosinophils were log transformed before the t-test.