Table 6.
Quantitative associations with glucose, insulin and diabetes outcomes, arranged by exposure type and listed in order of lowest to highest risk of bias.
| Exposure | Article (Study Wave) 1 |
Main Findings (Quantitative Measure [95% CI]) 2 | Bias 3 |
|---|---|---|---|
| Individual Characteristics | |||
| Sex | Sjöholm 2018 (ABC W4) |
No association between sex and HbA1c | M |
| Riley 2021 (SEARCH W2) | No association between sex and HbA1c | M | |
| Braun 1996 | Female (vs. male) associated with ↑ fasting and 2 h insulin (p < 0.05 trend) | H | |
| Obesity measures | Sayers 2004 (ABC W2) | ↑ weight (1 kg) and height (1 cm) at W2 associated with ↑ fasting insulin § (ratio 1.02 [1.01, 1.02]), HOMA-IR (1.02 [1.01, 1.02]), fasting glucose § (1.001 [1.001, 1.002]) |
M |
| Sayers 2009 (ABC W2) | ↑ weight (1 kg) at W2 associated with ↑ fasting insulin § (β 0.037 [0.028, 0.046]), fasting glucose (β 0.011 [0.0036, 0.019]) |
M | |
| Sayers 2013 (ABC W3) | ↑ weight (1 kg) at W3 associated with ↑ fasting insulin § (ratio 1.03 [1.02, 1.03]; R2 0.299), HOMA-IR § (1.03 [1.02, 1.04]), fasting glucose § (1.001 [1.001, 1.003]; R2 0.070)↑ height (1 cm) at W3 associated with ↑ fasting insulin § (ratio 1.03 [1.01, 1.05]; R2 0.055), HOMA-IR § (1.03 [1.01, 1.06]) ↑ BMI (1 kg/m2) at W3 associated with ↑ fasting insulin § (ratio 1.09 [1.07, 1.12]), HOMA-IR § (1.10 [1.08, 1.13]), fasting glucose § (1.007 [1.003, 1.01]) |
M | |
| Sellers 2008 (ABC W2) | zWC, zBMI positively correlated with HOMA-IR (r = 0.37, r = 0.29; p < 0.001) |
H | |
| Sevoyan 2019 (ABC W4) ^ |
↑ BMI category associated with ↑ elevated HbA1c (p < 0.001 trend) |
H | |
| Riley 2021 (SEARCH W2) | Obesity (vs. normal) associated with ↑ elevated HbA1c (aPR 2.52 [0.73, 8.63])—not statistically significant |
H | |
| Valery 2009 | BMI, WC positively correlated with HOMA-IR (r = 0.54, r = 0.72; p < 0.001) Overweight/obese (vs. normal) associated with ↑ HOMA-IR (3.58 vs. 2.25, p = 0.002), elevated fasting insulin (56 vs. 30%, p = 0.021), mean fasting insulin (18.74 vs. 11.96 mU/L, p = 0.001), mean HbA1c (5.55 vs. 5.39%, p = 0.037) |
H | |
| Daniel 2002 * | ↑ BMI category (22–24.9, 25–29.9, 30–34.9, ≥35 vs. <22 kg/m2) associated with ↑ odds of IGT (males: OR 3.3 [1.2, 9.9], 7.3 [2.9, 20.4], 11.4 [3.6, 36.6], 12.5 [3.2, 45.6]; females: OR 4.0 [1.5, 11.9], 6.1 [2.5, 16.6], 5.3 [1.7, 16.8], 9.3 [3.1, 29.0]), diabetes (males: OR 1.9 [0.3, 11.1], 6.2 [1.7, 28.6], 9.4 [1.9, 51.6], 8.1 [0.9, 56.3]; females: OR 10.3 [2.5, 69.5), 10.1 [2.6, 65.8], 25.7 [6.4, 168.1], 21.2 [4.7, 147.5]) |
H | |
| Braun 1996 | ↑ BMI at baseline associated with fasting insulin in upper tertile (vs. lower) at baseline (p < 0.05 trend), 2 h insulin in upper tertile at baseline ↑ BMI at follow-up associated with 2 h insulin in upper tertile (vs. lower) at follow-up (24.2 vs. 19.5 kg/m2, p < 0.05), abnormal glucose tolerance (IGT or T2DM vs. normal tolerance) at follow-up (25.6 vs. 20.8 kg/m2, p < 0.05) |
H | |
| Birth size | Sayers 2004 (ABC W2) | ↑ birth weight (500 g) associated with ↑ fasting insulin §
(ratio 1.04 [1.0, 1.1]), before adjusting for current child sizeAssociations did not persist after adjusting for current height or weight, indicating potential mediation |
M |
| Sayers 2009 (ABC W2) | No association between birth weight and insulin or glucose levels, before or after adjusting for current weight |
M | |
| Sayers 2013 (ABC W3) | ↑ birth weight (1 kg) associated with ↑ fasting glucose § (ratio 1.07 [1.03, 1.11]; R2 0.07) FGR (vs. non-FGR) associated with ↓ fasting glucose § (ratio 0.93 [0.89, 0.98]; R2 0.06) Positive and significant interactions between birth weight and height for insulin (p = 0.006) and HOMA-IR (p = 0.015) |
M | |
| Sjöholm 2018 (ABC W4) |
No association between birth weight and ideal HbA1c | M | |
| Environmental Factors | |||
| Remoteness | Mackerras 2003 (ABC W2) |
Urban (vs. remote) associated with ↑ fasting insulin (7 vs. 4 mU/L, p = 0.007) No association between remoteness and fasting glucose |
M |
| Sjöholm 2018 (ABC W4) |
No association between mother’s remoteness at birth and ideal HbA1c | M | |
1: ^ non-disaggregated data (majority Indigenous); * non-disaggregated data (majority aged <25 years); ABC = Aboriginal Birth Cohort; SEARCH = Study of Environment on Aboriginal Resilience and Child Health; W2 = follow-up wave 2. 2: ↑ = higher; ↓ = lower; β = linear regression coefficient; § = outcome measure log-transformed; aPR = adjusted prevalence ratio; BMI = body mass index; FGR = fetal growth restriction; HbA1c = glycated hemoglobin; HOMA-IR = Homeostasis Model Assessment of Insulin Resistance score; IGT = impaired glucose tolerance; OR = odds ratio; r = correlation coefficient; R2 = coefficient of determination (proportion of total variation in the outcome measure accounted for by the exposure); T2DM = type 2 diabetes mellitus; WC = waist circumference; zBMI = BMI z-score; zWC = WC z-score. 3: Risk of bias: H = high; M = moderate; L = low.