Association of risk factors with acute kidney injury† based on logistic regression (n=283)
| Age-adjusted and sex-adjusted model | Model adding physiological factors | Model adding occupational factors | |||||||
|---|---|---|---|---|---|---|---|---|---|
| AOR | 95% CI | p Value | AOR | 95% CI | p Value | AOR | 95% CI | p Value | |
| Per cent body mass lost‡ | 0.66 | 0.42 to 1.06 | 0.08 | 0.66 | 0.41 to 1.06 | 0.09 | 0.7 | 0.42 to 1.17 | 0.18 |
| Heat strain§ | 1.29 | 1.03 to 1.61 | 0.03* | 1.34 | 1.03 to 1.65 | 0.03* | 1.34 | 1.04 to 1.74 | 0.02* |
| Age in years | 0.99 | 0.97 to 1.02 | 0.65 | 0.99 | 0.95 to 1.02 | 0.42 | 0.98 | 0.94 to 1.02 | 0.34 |
| Sex | |||||||||
| Male (reference) | – | – | – | – | – | – | – | – | – |
| Female | 1.46 | 0.65 to 3.26 | 0.36 | 1.44 | 0.60 to 3.44 | 0.41 | 2.12 | 0.80 to 5.63 | 0.13 |
| BMI¶ | |||||||||
| Normal weight (<25) (reference) | – | – | – | – | – | – | |||
| Overweight (25–30) | 0.39 | 0.15 to 1.00 | 0.05 | 0.41 | 0.15 to 1.09 | 0.07* | |||
| Obese (>30) | 0.29 | 0.10 to 0.82 | 0.02* | 0.32 | 0.11 to 0.96 | 0.04* | |||
| Diabetes** | |||||||||
| HbA1c<5.7% (reference) | – | – | – | – | – | – | |||
| HbA1c≥5.7% | 2.45 | 0.93 to 6.46 | 0.07 | 2.63 | 0.93 to 7.41 | 0.07 | |||
| Blood pressure†† | |||||||||
| Normal blood pressure (<120/80) (reference) | – | – | – | – | – | – | |||
| Prehypertensive (120–139/80–89) | 0.64 | 0.24 to 1.70 | 0.37 | 0.73 | 0.26 to 2.06 | 0.56 | |||
| Hypertension (≤140/90) | 0.74 | 0.24 to 2.23 | 0.59 | 0.94 | 0.29 to 2.99 | 0.91 | |||
| History of kidney disease | |||||||||
| None (reference) | – | – | – | – | – | – | |||
| Personal or family history | 1.35 | 0.58 to 3.13 | 0.49 | 1.64 | 0.680 to 3.98 | 0.27 | |||
| Years in agricultural work | 1.03 | 0.98 to 1.08 | 0.21 | ||||||
| Payment method | |||||||||
| Hourly/salary (reference) | – | – | – | ||||||
| Piece rate | 4.24 | 1.56 to 11.52 | 0.01* | ||||||
| Farm task | |||||||||
| Picking | 1.1 | 0.41 to 2.92 | 0.86 | ||||||
| Other (reference)‡‡ | – | – | – | ||||||
| Model fit statistics | |||||||||
| AIC | 212.6 | 214.97 | 207.84 | ||||||
| BIC | 230.8 | 255.07 | 258.88 | ||||||
*Significant at α<0.05.
†Acute kidney injury based on KDIGO classification of elevations in serum creatinine.
‡Per cent body mass lost based on comparing preshift weight in kilograms and postshift weight in kilograms.
§Heat strain estimated by PSI with PSI≥7.5 signifying heat strain; Centered at PSI-4.
¶BMI (kg/m2) categorized based on WHO recommendations.
**HgbA1c from capillary blood sample.
††Blood pressure based on JNC7 categories.
‡‡Other includes all other farm tasks except picking.
AOR, adjusted OR;
BMI, body mass index; HbA1c, glycated haemoglobin; KDIGO, Kidney Disease: Improving Global Outcomes; PSI, physiological strain index.