Table 4.
Household Member Characteristics (n = 241)
| Characteristic | Total No. of Household Members at Risk (n = 241) |
Secondary Case (n = 155) |
No Secondary Case (n = 86) |
P Value |
OR (95% CI) |
|---|---|---|---|---|---|
| Child (<18 y) | 106 (44.0) | 68 (43.9) | 38 (44.2) | .962 | 0.99 (.58–1.68) |
| Adult | 135 (56.0) | 87 (56.1) | 48 (55.8) | .962 | 1.01 (.60–1.72) |
| Age, y, median (IQR) | 20.0 (12.0–45.0) | 19.0 (12.0–44.0) | 21.0 (10.3–47.8) | .678 | 1.00 (.98–1.01) |
| Age group, y | |||||
| <12 | 58 (24.1) | 34 (21.9) | 24 (27.9) | 1 (ref) | |
| 12–17 | 48 (20.0) | 34 (21.9) | 14 (16.3) | .194 | 1.71 (.76–3.86) |
| 18–39 | 49 (20.4) | 35 (21.6) | 14 (16.3) | .170 | 1.77 (.79–3.97) |
| 40–49 | 53 (22.1) | 32 (22.6) | 21 (24.4) | .851 | 1.08 (.50–2.30) |
| 50–65 | 33 (13.8) | 20 (12.9) | 13 (15.1) | .853 | 1.09 (.45–2.60) |
| Sex (female) | 101 (41.9) | 62 (40.0) | 39 (45.3) | .420 | 0.80 (.47–1.37) |
| BMI classb | |||||
| Normal weight | 150 (66.1) | 95 (65.5) | 55 (67.1) | 1 (ref) | |
| Obesity | 13 (5.7) | 9 (6.2) | 4 (4.9) | .672 | 1.30 (.38–4.43) |
| Overweight | 59 (26.0) | 37 (25.5) | 22 (26.8) | .933 | 0.97 (.52–1.82) |
| Underweight | 5 (2.2) | 4 (2.8) | 1 (1.2) | .458 | 2.32 (.25–21.24) |
| Underlying medical conditionc | 27 (11.2) | 14 (9.0) | 13 (15.1) | .155 | 0.56 (.25–1.25) |
| Smoking (yes) | 7 (2.9) | 4 (2.6) | 3 (3.5) | .689 | 0.733 (.16–3.35) |
| Nationality (other)d | 2 (0.8) | 0 (0.0) | 2 (2.4) | ||
| Relationship to index case | |||||
| Childe | 117 (48.5) | 78 (50.3) | 39 (45.3) | 1 (ref) | |
| Spouse | 58 (24.1) | 39 (25.2) | 19 (22.1) | .939 | 1.03 (.53–2.01) |
| Other adult | 3 (1.2) | 3 (1.9) | 0 (0.0) | ||
| Parent | 44 (18.3) | 25 (16.1) | 19 (22.1) | .248 | 0.66 (.32–1.34) |
| Sibling | 19 (7.9) | 10 (6.5) | 9 (10.5) | .239 | 0.56 (.21–1.48) |
Data are presented as No. (%) unless otherwise indicated. The per-person secondary attack rate was 64.3%.
Abbreviations: BMI, body mass index; CI, confidence interval; IQR, interquartile range; OR, odds ratio.
Some numbers might not add up to 241 due to missing values.
BMI categories for index cases and household members 2 to <18 years of age were defined as BMI z-score < –2, underweight; –2 to 1, normal weight; 1–2, overweight; >2, obesity (source: Centers for Disease Control and Prevention, https://www.cdc.gov/growthcharts/zscore.htm, accessed 28 September 2021). BMI categories for index cases and household members ≥18 years of age were defined as <18.5 kg/m2, underweight; 18.5–24.9 kg/m2, normal weight; 25.0–29.9 kg/m2, overweight; ≥30.0 kg/m2, obesity.
Cardiovascular disease, lung disease, immune disorder, diabetes, rheumatic disorder, and other disorders.
Other than Dutch.
Children could be either <18 years old or ≥18 years old if their role was a child within a household.