Volume 17, Number 7—July 2011
Research
Epidemiology of Influenza-like Illness during Pandemic (H1N1) 2009, New South Wales, Australia
, Margo Barr, Sarah V. Thackway, and C. Raina MacIntyre
Table 5
Risk factors evaluated for influenza-like illness, New South Wales, Australia, July–September 2009*
| Factor | Factor prevalence, % (95% CI) | Reference category† | Age group analyzed (no. respondents)‡ | Relative risk (95% CI) | p value§ |
|---|---|---|---|---|---|
| Age, y | >65 y | All ages (2,909) | |||
| 0–15 | 21.4 (19.4–23.5) | 5.96 (3.25–10.93) | <0.001 | ||
| 16–34 | 26.0 (23.2–28.8) | 4.76 (2.35–9.62) | <0.001 | ||
| 35–49 | 21.7 (19.4–23.9) | 3.55 (1.86–6.79) | <0.001 | ||
| 50–64 |
17.7 (16.1–19.3) |
3.00 (1.57–5.71) |
0.001 |
||
| Female sex¶ |
50.5 (47.8–53.2) |
Male |
All ages (2,909) |
1.31 (0.89–1.94) |
0.173 |
| Rural region¶ | 29.9 (28.4–31.4) | Urban | All ages (2,909) | 1.26 (0.87–1.84) | 0.227 |
| Socioeconomically disadvantaged¶ # |
38.4 (35.9–40.9) |
Not disadvantaged |
All ages (2,909) |
0.93 (0.63–1.38) |
0.729 |
| >2 children in household¶ | 34.5 (31.9–37.2) | <2 children residing in household | All ages (2,909) | 0.75 (0.51–1.10) | 0.142 |
| >3 persons in household¶ |
67.7 (65.6–69.7) |
1–2 persons in household |
All ages (2,909) |
1.14 (0.75–1.72) |
0.536 |
| Seasonal influenza vaccination in past 12 mo¶ | 25.6 (23.5–27.7) | No seasonal influenza vaccination in past 12 mo | >6 mo (2,888) | 0.80 (0.49–1.31) | 0.372 |
| Current asthma¶ |
11.4 (9.8–13.0) |
No current asthma |
>2 y (2,831) |
1.15 (0.69–1.92) |
0.595 |
| Body mass index¶ | >2 y (2,831) | ||||
| Obese | 18.0 (15.9–20.1) | Healthy or underweight | 2.14 (1.31–3.48) | 0.002 | |
| Overweight |
28.6 (26.3–31.0) |
Healthy or underweight |
1.06 (0.67–1.67) |
0.816 |
|
| Current diabetes or high blood glucose¶ | 8.0 (6.7–9.2) | No current diabetes or high blood glucose | >9 y (2,636) | 0.97 (0.50–1.91) | 0.936 |
| Daily smoker¶ | 13.0 (10.8–15.1) | Occasional/ex-/non-smoker | >16 y (2,431) | 1.94 (1.06–3.54) | 0.031 |
| Inadequate physical activity¶ | 48.6 (45.6–51.7) | Adequate physical activity | >16 y (2,431) | 1.04 (0.65–1.65) | 0.881 |
| Risky alcohol drinking¶ |
31.6 (28.6–34.7) |
Low-risk alcohol drinking |
>16 y (2,431) |
1.25 (0.76–2.05) |
0.378 |
| High or very high psychological distress score¶ |
11.2 (9.4–13.1) |
Moderate or low psychological distress score |
>16 y (2,431) |
1.41 (0.85–2.35) |
0.182 |
| Pneumococcal vaccination in past 5 y¶ | 28.3 (25.7–30.9) | No pneumococcal vaccination in the past 5 y (adjusted for age) | >50 y (1,633) | 1.20 (0.56–2.56) | 0.640 |
*CI, confidence interval.
†Not stated and “Don’t know” responses were included in the reference category. Among parameters with any such responses, the proportions were index of socioeconomic disadvantage 0.9%, vaccinated against influenza in the past 12 mo 1.0%, current asthma 0.3%, body mass index 5.2%, smoking status 0.1%, psychological distress score 3.0%, alcohol use 1%, and pneumococcal vaccination 7.0%.
‡Some questions are only collected on selected age groups, so sample sizes vary.
§Significant results at the 5% level are in boldface.
¶Adjusted for age.
#Disadvantaged = lowest 2 quintiles of the Australian index of relative socioeconomic disadvantage based on the respondent's residential postcode; not disadvantaged = upper 3 quintiles.