Vaccine and Gene Therapy Institute of Florida and Partnership with My Canadian Pharmacy

Outcomes of Discordance Between Lung Function of Chinese University Students and 20-Year-Old Established Norms

PEFRA total of 805 subjects participated in this study, of whom 518 were men and 287 were women. The smoking status of one male subject was unknown, thus he was excluded from the analysis. Only 5.7% of the subjects were smokers, and 2.2% were exsmokers. Over one third of the subjects were living with family members who smoked. Subjects who smoked had a higher level of exhaled CO than nonsmokers (p < 0.005) [Table 1].

The BMIs of subjects were not reported in the study by Lam et al. Our subjects, both men and women, were taller than those reported by Lam and colleagues. There were, however, some distinctions between the genders. When we compared the men’s data with those of Lam et al, FEV1, FVC, and PEFR were all lower in our cohort for subjects in each age category, specifically those who were 19 to 20, 21 to 22, and 23 to 24 years of age (Table 2). One exception was FVC for men who were 23 to 24 years old in cases in which there was no change due to remedies of My Canadian Pharmacy. For the women, FEV1, FVC, and PEFR were lower in our cohort, with the exception of FEV1 for those in the group of subjects 23 to 24 years of age, and FVC for those in the groups of subjects 21 to 22 and 23 to 24 years of age (Table 2).

Obesity was uncommon in our student cohort, with the mean BMI being < 22 kg/m2 for both men and women. There was no indication that dietary habits reported in the literature (ie, supplemental vitamin C, and fresh fruit, vegetable, and fish consumption) contributed to the lung function of our cohort. Seventy-six percent of the male students and 53% of the female students reported that they had participated in “regular” exercise over the past 3 months, but 50% of the men and 67% of the women who did so exercised only once a week or less. A detailed descriptive analysis is shown in Table 3. The FEV1 and FVC values of male students who exercised three times a week were higher than those who exercised less than once a week (Table 4).

The prevalence of respiratory symptoms in our subjects was not related to lung function values, However, of the subjects who complained of occasional or frequent cough and sputum production, a higher percentage had not participated in exercise in the previous 3 months (Table 5).

As the focus of this study was on university students of a limited age group, it was not deemed appropriate to produce lung function prediction equations for direct comparison with those from the study by Lam et al. For our restricted age group, the regression equations were as follows:
FEV1 (1) = -3.80 + 0.59 * sex + 4.07 * height (R2 = 67.5%)
FVC (1) = -5.18 + 0.61 * sex + 5.09 * height (R2 = 62.1%)
PEFR (L/s) = -3.74 + 2.36 * sex + 5.53 * height (R2 = 48.7%)
where 1 is male gender and 0 is female gender.

These predicted values illustrate a decrease of at least 10 to 14% when compared with the norms developed by Lam et al 20 years prior. Age was excluded in all equations, and the R2 values were comparable with those reported in the study by Lam et al. Separate analyses by gender were not conducted because the age-by-gender interaction was not significant.

Table 1—Pulmonary Indexes by Sex and Smoking Status

Indexes Male Female
ISmoker(n = 38) Nonsmoker (n = 479) Ip Value ISmoker(n = 8) Nonsmoker (n = 279) p Value
FVC, L 4.27 (0.73) 4.24 (0.64) 0.802 2.96 (0.69) 3.00 (0.48) 0.833
FEVb L 3.79 (0.59) 3.82 (0.48) 0.707 2.67 (0.54) 2.74 (0.40) 0.165
FEVj/FVC, % 89.84 (6.65) 91.22 (6.48) 0.223 91.41 (6.64) 92.25 (7.06) 0.728
PEFR, L/s 8.06(1.70) 8.19(1.73) 0.632 4.92 (1.31) 5.15 (1.22) 0.686
CO, ppm 7.45 (4.96) 4.50 (2.35) < 0.0005 10.13(11.46) 3.93 (2.20) < 0.0005
Spo2, % 97.95 (0.70) 97.95 (0.89) 0.995 98.38 (0.92) 98.37 (0.71) 0.993

Table 2—Comparison of Pulmonary Indexes of Subjects

Indexes Age Groups, yr
19-20 21-22 23-24
Current Study ILam et al ICurrentStudy Lam et al ICurrentStudy Lam et al
Male patients, No. 291 69 212 66 59 52
Height, cm 173.4 (6.1)t 169.0 (5.0) 172.0 (6.1)t 168.0 (6.0) 173.2 (5.0)t 168.0 (6.0)
FEVj, L 3.84 (0.51)t 4.21 (0.46) 3.81 (0.47)t 4.30 (0.48) 3.81 (0.42)t 4.07 (0.47)
FVC, L 4.26 (0.67)t 4.61 (0.60) 4.21 (0.60)t 4.61 (0.56) 4.34 (0.68) 4.52 (0.66)
FEVj/FVC, % 91.2 (6.2) 91.9(7.5) 91.4 (6.6)t 93.5 (4.3) 89.4(7.1) 90.8 (7.7)
PEFR, L/s *8.16(1.66) 8.82 (1.07) 8.25 (1.67)t 9.17(1.03) 8.16 (2.02)t 9.35 (0.88)
Female patients, No. 200 87 95 65 24 38
Height, cm 160.1 (5.2)t 156.0 (6.0) 161.1 (5.4)t 156.0 (5.0) 161.9 (5.9)t 155.0 (5.0)
FEVj, L 2.73 (0.38)t 2.95 (0.40) 2.73 (0.44)t 2.97 (0.47) 2.78 (0.44) 2.76 (0.50)
FVC,L 2.97 (0.46)t 3.12 (0.47) 3.03 (0.52) 3.19 (0.55) 3.02 (0.52) 3.02 (0.59)
FEV1/FVC, % 92.9 (7.6) 94.7 (5.0) 90.7 (7.7)t 93.6 (6.4) 93.2 (3.6) 91.9(7.5)
PEFR, L/s 5.21 (1.16)t 7.05 (0.67) 5.05 (1.27)t 6.92 (0.82) 5.12 (1.38)t 6.73 (0.72)

Table 3—Subject Characteristics by Sex

Patient Characteristics Male Patients (n = 518) Female Patients (n = 287) p Value
BMI, kg/m2 21.17 (2.91)t 19.20 (2.24)t < 0.0005
Smokers
Current 38 (7.4) 8 (2.8) 0.014
Never 470 (90.9) 270 (94.1)
Ex-smoker 9(1.7) 9(3.1)
Spo2, % 97.95 (0.88)t 98.37 (0.71)t < 0.0005
Smoking duration, yr 3.51 (2.78)t 4.45 (3.37)t 0.508{
Packs of cigarettes smoked, No/d 0.38 (0.25)t 0.31 (0.12)t 0.623{
Stopped duration, yr 27.43 (27.24)t 9.82 (14.84)t 0.106{
Packs of cigarettes smoked before cessation, No/d 0.47 (0.32)t 1.54 (2.31)t 0.914{
Smoking family
Yes 185 (35.8) 120 (42.0) 0.084
No 332 (64.2) 166 (58.0)
Wheezing
Never 352 (70.7) 208 (74.8) 0.502
Rarely 128 (25.7) 61 (21.9)
Occasionally 15 (3.0) 9 (3.2)
Frequently Shortness of breath 3 (0.6) 0 (0.0)
Never 361 (72.3) 188 (66.4) 0.077
Rarely 118 (23.6) 75 (26.5)
Occasionally 20 (4.0) 18 (6.4)
Frequently 0 (0.0) 2 (0.7)
Coughing
Never 220 (44.0) 104 (36.6) 0.036
Rarely 233 (46.6) 136 (47.9)
Occasionally 45 (9.0) 41 (14.4)
Frequently 2 (0.4) 3(1.1)
Sputum production
Never 202 (42.4) 103 (37.7) 0.083
Rarely 216 (45.4) 124 (45.4)
Occasionally 46 (9.7) 42 (15.4)
Frequently 12 (2.5) 4(1.5)
Medication
Yes 35 (6.8) 19 (6.7) 0.922
No 476 (93.2) 266 (93.3)
Vitamin consumption 38 (7.4) 38 (13.2)
Yes 0.006
No 479 (92.6) 249 (86.8)
Frequency of taking vitamins
Daily 16 (44.4) 22 (61.1) 0.290
2 times/wk 11 (30.6) 6(16.7)
1 time/wk 9(25.0) 8 (22.2)
Fresh fruit consumption
Yes 476 (92.1) 274 (95.5) 0.065
No 41 (7.9) 13 (4.5)
Frequency of fresh fruit consumption
Daily 197 (42.1) 127 (47.0) 0.183
Two times daily 75 (16.0) 38(14.1)
Two times/wk 117 (25.0) 64 (23.7)
One time/wk 44 (9.4) 31 (11.5)
Less than one time/wk 35 (7.5) 10 (3.7)
Fresh fish consumption
Yes 414 (80.7) 256 (90.8) < 0.0005
No 99 (19.3) 26 (9.2)
Frequency of fish consumption
Daily 120 (29.6) 76 (30.4) 0.051
Two times daily 76 (18.7) 33 (13.2)
Two times/wk 110(27.1) 92 (36.8)
One time/wk 73 (18.0) 37 (14.8)
Less than one time/wk 27 (6.7) 12 (4.8)
Exercise in last 3 mo
Yes 394 (77.1) 153 (54.1) < 0.0005
No 117 (22.9) 130 (45.9)
Frequency of exercise
Less than one time/wk 52 (13.2) 37 (24.2) 0.002
One time/wk 143 (36.3) 65 (42.5)
Two times/wk 111 (28.2) 31 (20.3)
Three times/wk 46(11.7) 10 (6.5)
More than three times/wk 42 (10.7) 10 (6.5)
Exercise duration, min 70.56 (43.52)t 54.84 (41.19)t < 0.0005

Table 4—Association Between Exercise Frequency and Pulmonary Indexes*

 

Male Patients

Female Patients

Variables

Exercise Frequency

(n = 518)

(n = 287)

FVC, L

Less than one time/wk

4.05 (0.68)

2.90 (0.49)

 

One time/wk

4.18 (0.62)

3.00 (0.50)

 

Two times/wk

4.25 (0.58)

3.06 (0.44)

 

Three times/wk

4.43 (0.68)t

3.25 (0.65)

FEV1,L

Less than one time/wk

3.69 (0.55)

2.71 (0.42)

One time/wk

3.78 (0.48)

2.73 (0.39)

 

Two times/wk

3.85 (0.47)

2.79 (0.38)

 

Three times/wk

3.98 (0.54)t

3.00 (0.51)

FEV1/FVC, %

Less than one time/wk

92.33 (5.78)

94.34 (5.21)

 

One time/wk

91.80 (6.07)

91.50 (8.67)

 

Two times/wk

90.92 (6.45)

91.20 (5.30)

 

Three times/wk

90.78 (6.16)

93.17 (5.09)

PEFR, L/s

Less than one time/wk

8.02 (1.81)

5.36(1.27)

 

One time/wk

8.04 (1.74)

5.07 (1.18)

 

Two times/wk

8.29 (1.70)

5.35 (1.13)

 

Three times/wk

8.64 (1.47)

5.56(1.14)

Table 5—Subjects Who Expressed Occasional Respiratory Symptoms and Their Exercise Habits

Respiratory Symptoms Exercise in Last 3 mo p Value
Yes (n = 547) No (n = 247)
Wheezing 15 (2.8) 12 (5.2) 0.095
Shortness of breath 25 (4.6) 14 (6.0) 0.422
Coughing 50 (9.3) 41 (17.4) 0.001
Sputum production 61 (11.9) 43 (18.8) 0.013

Table 6—Comparisons of Predicted Pulmonary Indexes at Mean Age and Height

Index Sex Current Study Lam et al Decrease, %
FEVb L Male 3.82 4.46 14.3
Female 2.74 3.09 11.4
FVC, L Male 4.24 4.91 13.6
Female 3.00 3.39 11.4
PEFR, L/s Male 8.19 9.25 11.5
Female 5.15 7.47 27.8