Background
Methods
Participants and Measurements
Measures
Quartiles of baseline BMI [n (% in row)] | ||||
---|---|---|---|---|
Categories of baseline BMI based on NHLBI BMI cutpoints
|
Q1 <21.3 kg/m
2
|
Q2 21.3–<23.4 kg/m
2
|
Q3 23.4–<26.4 kg/m
2
|
Q4 ≥ 26.4 kg/m
2
|
<18.5 kg/m2
| 193 (100) | 0 (0) | 0 (0) | 0 (0) |
18.5–24.9 kg/m2
| 990 (35) | 1184 (41) | 683 (24) | 0 (0) |
25–29.9 kg/m2
| 0 (0) | 0 (0) | 500 (45) | 621 (55) |
≥ 30 kg/m2
| 0 (0) | 0 (0) | 0 (0) | 563 (100) |
Statistical Methods
Results
Description of Study Population
Quartiles of Baseline BMI | ||||
---|---|---|---|---|
Q1 <21.3 kg/m
2
|
Q2 21.3–<23.4 kg/m
2
|
Q3 23.4–<26.4 kg/m
2
|
Q4 ≥ 26.4 kg/m
2
| |
(n = 1117)
|
(n = 1191)
|
(n = 1215)
|
(n = 1211)
| |
Age (Years)
| 24.3 (3.7) | 24.7 (3.5) | 25.1 (3.6) | 25.3 (3.5) |
FVC (L)
| 4.02 (0.88) | 4.40 (0.96) | 4.58 (1.06) | 4.19 (1.05) |
FEV
1
(L)
| 3.38 (0.68) | 3.64 (0.75) | 3.74 (0.82) | 3.44 (0.82) |
FEV
1
/FVC
| 85 (7) | 83 (6) | 82 (6) | 83 (6) |
Physical activity (exercise units)
| 395 (275) | 462 (299) | 459 (317) | 375 (290) |
Alcohol (mg/day)
| 10.6 (19.0) | 12.9 (22.8) | 13.5 (21.0) | 11.4 (22.4) |
Education (% ≤ high school)
| 39.8 | 37.6 | 35.6 | 42.6 |
Race (Blacks) (%)
| 44.1 | 45.1 | 48.8 | 64.4 |
Sex (Male) (%)
| 32.6 | 51.2 | 57.5 | 43.0 |
Prevalence of asthma at year 0 (%)
| 9.0 | 9.2 | 10.9 | 10.2 |
Cumulative incidence of asthma during 10 years of follow-up (%)
| 6.8 | 4.9 | 5.4 | 8.1 |
Prevalence of ex-smokers (%)
| 14.2 | 13.0 | 15.1 | 12.1 |
Prevalence of current smoking ≤ 15 cigs/day (%)
| 21.7 | 21.6 | 19.1 | 20.9 |
Prevalence of current smoking > 15 cigs/day (%)
| 9.9 | 9.9 | 10.0 | 9.8 |
Quartiles of baseline BMI [n (% in column)] | ||||
---|---|---|---|---|
Categories of Change in BMI
|
Q1 <21.3 kg/m
2
|
Q2 21.3–<23.4 kg/m
2
|
Q3 23.4–<26.4 kg/m
2
|
Q4 ≥ 26.4 kg/m
2
|
≤ 0 kg/m2
| 115 (14) | 149 (17) | 146 (16) | 138 (15) |
0.1–0.9 kg/m2
| 137 (17) | 128 (15) | 103 (12) | 63 (7) |
1–2.4 kg/m2
| 232 (29) | 227 (26) | 187 (21) | 136 (15) |
2.5–5.9 kg/m2
| 254 (31) | 270 (31) | 323 (36) | 292 (33) |
≥ 6 kg/m2
| 70 (9) | 102 (12) | 132 (15) | 263 (29) |
Lung Function and BMI: Association between year 0 BMI and lung function
Quartiles of baseline BMI | 10-year Change in lung function value | ||
---|---|---|---|
All participants
|
FVC
|
FEV1
|
FEV1/FVC
|
<21.2 kg/m2
| 71 (-43 – 184) | 60 (-38 – 159) | -0.07% (-1.40% – 1.26%) |
21.3–<23.4 kg/m2
| 19 (-94 – 133) | 18 (-79 – 116) | 0.29% (-1.03% – 1.62%) |
23.4–<26.4 kg/m2
| -72 (-186 – 41) | -28 (-125 – 70) | 1.00% (-0.33% – 2.33%) |
≥ 26.4 kg/m2
| -185 (-298 – -71) | -64 (-161 – 34) | 2.03% (0.71% – 3.36%) |
p trend | <0.0001 | <0.0001 | <0.0001 |
Never smoker, never asthma
| |||
<21.2 kg/m2
| 129 (-37 – 294) | 76 (-62 – 215) | -0.84% (-2.63% – 0.95%) |
21.3–<23.4 kg/m2
| 78 (-87 – 244) | 29 (-109 – 168) | -0.60% (-2.39% – 1.18%) |
23.4–<26.4 kg/m2
| -18 (-184 – 147) | -28 (-166 – 111) | 0.05% (-1.73% – 1.84%) |
≥ 26.4 kg/m2
| -138 (-304 – 27) | -47 (-186 – 91) | 1.60% (-0.19% – 3.39%) |
p trend | <0.0001 | <0.0001 | <0.0001 |
Lung Function and BMI: Association Between Change in BMI and Change in Lung Function
Quartiles of baseline BMI *+
| ||||
---|---|---|---|---|
<21.3 kg/m
2
|
21.3–<23.4 kg/m
2
|
23.4–<26.4 kg/m
2
|
≥ 26.4 kg/m
2
| |
2, 5 and 10 year FVC change (p interaction < 0.0001)
| ||||
Categories of Change in BMI
|
Q1
|
Q2
|
Q3
|
Q4
|
≤ 0 kg/m2
| 5 (-14 – 24) | 32 (14 – 49) | 49 (32 – 67) | 22 (4 – 40) |
0.1–0.9 kg/m2
| 15 (1 – 30) | 22 (8 – 37) | 22 (8 – 37) | 15 (0 – 31) |
1–2.4 kg/m2
| 53 (38 – 67) | 19 (4 – 33) | -13 (-27 – 2) | -63 (-80 – -46) |
2.5–5.9 kg/m2
| 65 (46 – 83) | 1 (-17 – 18) | -69 (-85 – -53) | -146 (-161 – -130) |
≥ 6 kg/m2
| 5 (-37 – 46) | -96 (-132 – -60) | -178 (-208 – -148) | -264 (-286 – -243) |
2, 5, and 10 year FEV
1
change (p interaction < 0.0001)
| ||||
Categories of Change in BMI
|
Q1
|
Q2
|
Q3
|
Q4
|
≤ 0 kg/m2
| -38 (-56 – -19) | -18 (-35 – -2) | -5 (-21 – 11) | -11 (-22 – 6) |
0.1–0.9 kg/m2
| -31 (-45 – -17) | -24 (-38 – -10) | -22 (-36 – -8) | -30 (-45 – -16) |
1–2.4 kg/m2
| -30 (-44 – -16) | -60 (-73 – -46) | -66 (-80 – -52) | -81 (-97 – -64) |
2.5–5.9 kg/m2
| -54 (-71 – -36) | -95 (-111 – -78) | -121 (-137 – -106) | -136 (-151 – -121) |
≥ 6 kg/m2
| -110 (-149 – -70) | -147 (-181 – -112) | -201 (-230 – -173) | -216 (-236 – -195) |
2, 5, and 10 year FEV
1
/FVC change (p interaction < 0.0001)
| ||||
Categories of Change in BMI
|
Q1
|
Q2
|
Q3
|
Q4
|
≤ 0 kg/m2
| -0.96 (-1.30 – -0.63) | -1.03 (-1.33 – -0.74) | -0.99 (-1.29 – -0.70) | -0.70 (-1.01 – -0.40) |
0.1–0.9 kg/m2
| -1.03 (-1.28 – -0.78) | -1.03 (-1.28 – -0.78) | -1.01 (-1.26 – -0.75) | -1.01 (-1.27 – -0.74) |
1–2.4 kg/m2
| -1.85 (-2.10 – -1.61) | -1.71 (-1.95 – -1.46) | -1.24 (-1.49 – -0.98) | -0.68 (-0.97 – -0.39) |
2.5–5.9 kg/m2
| -2.59 (-2.91 – -2.28) | -2.18 (-2.47 – -1.89) | -1.55 (-1.82 – -1.27) | -0.51 (-0.78 – -0.25) |
≥ 6 kg/m2
| -3.30 (-4.01 – -2.59) | -2.10 (-2.72 – -1.48) | -1.60 (-2.12 – -1.08) | -0.11 (-0.48 – 0.26) |