Table 1.
Descriptive characteristics of the two pediatric cohorts.
| Variables | Birth Cohort | Newly Diagnosed Cohort | ||||
|---|---|---|---|---|---|---|
| Patient | Control | p-Value 1 | Patient | Sibling | p-Value | |
| (n = 470) | (n = 500) | (n = 460) | (n = 453) | |||
| Basic characteristics | ||||||
| Sex | ||||||
| Female, n/% of total | 231/49.1 | 231/46.2 | 0.39 | 218/47.4 | 198/43.7 | 0.29 |
| Male, n/% of total | 239/50.9 | 269/53.8 | 242/52.6 | 255/56.3 | ||
| Age at onset 2 | ||||||
| Median/ | 8.2/ | 10.4/ | 10.3/ | 0.41 | ||
| Q1–Q3 3, years | 4.8–11.0 | 7.4–12.5 | 7.8–12.8 | |||
| Pregnancy and birth | ||||||
| Gestational age | ||||||
| Median/Q1–Q3, weeks | 40/39–41 | 40/39–40 | 0.58 | |||
| Birth weight, n/% of total | ||||||
| <2500 g | 19/4.0 | 30/6.0 | ||||
| 2500–4499 g | 441/93.8 | 460/92.0 | 0.38 | |||
| >4500 g | 10/2.1 | 10/2.0 | ||||
| Birth length | ||||||
| Median/Q1–Q3, cm | 52/51–53 | 52/50–53 | 0.37 | |||
| Mother’s age at child’s birth | ||||||
| Median/Q1–Q3, years | 28/25–31 | 28/25–31 | 0.84 | |||
| Season and time period of blood sampling | ||||||
| Season, n/% of total 4 | ||||||
| Winter | 104/22.1 | 106/21.2 | 117/25.4 | 118/26.0 | ||
| Spring | 112/23.8 | 125/25.0 | 0.49 | 115/25.0 | 116/25.6 | 0.11 |
| Summer | 113/24.0 | 137/27.4 | 105/22.8 | 126/27.8 | ||
| Autumn | 141/30.0 | 132/26.4 | 123/26.7 | 93/20.5 | ||
| Time period, n/% of total 5 | ||||||
| 1. 1981–1987 or 1997–1999 | 177/37.7 | 171/34.2 | 143/31.1 | 210/46.4 | ||
| 2. 1987–1991 or 2000–2002 | 152/32.3 | 177/35.4 | 0.48 | 94/20.4 | 45/10.0 | <0.0001 |
| 3. 1991–1999 or 2003–2005 | 141/30.0 | 152/30.4 | 223/48.5 | 198/43.7 | ||
1 When comparing groups, the statistical tests used are chi-square test for categorical, and Mann-Whitney U for numerical variables; 2 For the newly diagnosed cohort this equals the age at blood sampling for both patients (within 3 months after onset of childhood T1D) and siblings; 3 First and third quartile; 4 Winter (December through February), spring (March through May), summer (June through August) and autumn (September through November); 5 The first time period represents the birth cohort and the second represents the newly diagnosed cohort. T1D, childhood type 1 diabetes.