Table 1.

Selected demographic, lifestyle, and occupational characteristics of the study cohort

CharacteristicOverall, n=350Men, n=263Women, n=87
Personal and lifestyle factors
 Age, yr, mean (SD)23.9 (3.7)23.7 (3.8)24.2 (3.6)
 Educational level, n (%)
  Illiteracy18 (5.1)18 (6.8)0 (0)
  Primary school176 (50.3)133 (50.6)43 (49.4)
  Secondary school138 (39.5)100 (38.0)38 (43.7)
  Higher education18 (5.1)12 (4.6)6 (6.9)
 Body mass index, median (IQR)22.7 (21.0–25.0)22.4 (20.8–24.1)24.5 (21.9–30.0)
 Systolic BP, mm Hg, median (IQR)117 (109–124)119 (111–125)109 (103–119)
 Diastolic BP, mm Hg, median (IQR)68 (63–73)68 (63–74)68 (63–72)
 Household income, Córdobas per 1 mo, median (IQR)6000 (4000–9200)6000 (4000–10,000)5120 (3380–8144)
 Family history of CKD, n (%)
  Yes165 (47.1)126 (47.9)39 (44.8)
  No185 (52.9)137 (52.1)48 (55.2)
 Annual alcohol consumption, g, median (IQR)0·0 (0–849)82.9 (0–1350)0.0 (0–0)
 Smoking pack-year, median (IQR)0·0 (0–0)0·0 (0–1)0.0 (0–0)
 NSAID use ever, n (%)
  Never58 (16.6)49 (18.6)9 (10.3)
  Occasionally251 (71.7)185 (70.3)66 (75.9)
  Regularly31 (8.9)23 (8.8)8 (9.2)
  Daily10 (2.8)6 (2.3)4 (4.6)
 Water sources, n (%)
  Piped water186 (53.1)139 (52.9)47 (54.0)
  Dug well126 (36.0)98 (37.2)28 (32.2)
  Drilled well38 (10.9)26 (9.9)12 (13.8)
 Water hardness, n (%)
  Soft0 (0.0)0 (0.0)0 (0.0)
  Moderately hard97 (27.7)67 (25.4)30 (34.5)
  Hard160 (45.7)123 (46.8)37 (42.5)
  Very hard93 (26.6)73 (27.8)20 (23.0)
 Total liquid in last 24 h, median (IQR)5.0 (3.7–6.3)5.6 (4.2–6.7)3.6 (2.5–4.5)
Occupational factors
 Current occupation, n (%)
  Sugarcane55 (15.7)45 (17.1)10 (11.5)
  Banana work14 (4.0)13 (4.9)1 (1.1)
  Other agricultural work115 (32.9)109 (41.5)6 (6.9)
  Commerce14 (4.0)5 (1.9)9 (10.3)
  Construction10 (2.9)10 (3.8)0 (0)
  Fishing7 (2.0)7 (2.7)0 (0)
  Homeworker54 (15.4)0 (0)54 (62.1)
  Student6 (1.7)4 (1.5)2 (2.3)
  Unemployed51 (14.6)49 (18.6)2 (2.3)
  Other occupationsa24 (6.8)21 (8.0)3 (3.5)
 Main sugarcane role (if ever worked in sugarcane), n (%)
  Cane cutter81 (23.2)81 (30.8)0 (0)
  Seed cutter56 (16.3)56 (21.3)0 (0)
  Seeder67 (19.2)47 (17.9)21 (24.1)
  Cane cleaner26 (7.4)17 (6.5)9 (10.4)
  Pesticide applicator4 (1.1)4 (1.5)0 (0)
  Cane irrigator8 (2.3)8 (3.0)0 (0)
  Driver4 (1.1)4 (1.5)0 (0)
  Never worked in sugarcane103(29.4)46 (17.5)57 (65.5)
 Current or previous banana work, n (%)
  Yes56 (16.0)47 (17.9)9 (10.3)
  No294 (84.0)216 (82.1)78 (89.7)
 Years in sugarcane, mean (SD)2.2 (2.8)2.8 (2.8)0.67 (1.7)
 Years in agricultural, mean (SD)3.6 (4.4)4.3 (4.5)1.2 (3.3)
 Work carried out,b n (%)
  Indoors136(38.9)69 (26.2)67 (77.0)
  Outdoors214 (61.1)194 (73.8)20 (23.0)
 Work in a hot environment,b n (%)
  Irregularly137 (39.2)92 (35.0)45 (51.7)
  Regularly74 (21.1)57 (21.7)17 (19.5)
  Frequently139 (39.7)114 (43.3)25 (28.8)
  Always0 (0)0 (0)0 (0)
 Shade availability,b n (%)
  Yes254 (72.6)190 (72.2)64 (73.6)
  No96 (27.4)73 (27.8)23 (26.4)
 Duration of breaks, min,b median (IQR)20 (10–30)15.0 (10–30)30.0 (20–60)
 Physical effort at work,c n (%)
  Did not work15 (4.3)14 (5.3)1 (1.2)
  Slight142 (40.6)100 (38.0)42 (48.3)
  Moderate155 (44.2)119 (45.3)36 (41.4)
  Hard38 (10.9)30 (11.4)8 (9.2)
 Glyphosate use,b,d n (%)
  Yes77 (22.0)77 (29.3)0 (0)
  No273 (78.0)186 (70.7)87 (100.0)
 Paraquat use,b,d n (%)
  Yes44 (12.6)44 (16.7)0 (0)
  No306 (87.4)219 (83.3)87 (100.0)
 Cypermethrin use,b,d n (%)
  Yes75 (21.4)73 (27.7)2 (2.3)
  No275 (78.6)190 (72.2)85 (97.7)
 Methomyl use,b,d n (%)
  Yes12 (3.4)12 (4.6)0 (0)
  No338 (96.6)251 (94.4)87 (100.0)
Clinical history/symptoms
 Heat/dehydration symptoms,b n (%)
  Yes240 (68·6)175 (66·5)65 (74·7)
  No110 (31·4)88 (33·5)22 (25·3)
 UTI in the previous year, n (%)
  Yes91 (26.0)56 (21.3)35 (40.2)
  No259 (74.0)207 (78.7)52 (59.8)
 Weight loss,b n (%)
  Yes63 (18.0)55 (20.9)8 (9.2)
  No287 (82.0)208 (79.1)79 (90.8)
 Dysuriab
  Yes94 (26.9)72 (27.4)22 (25.3)
  No256 (73.1)191 (72.6)65 (74.7)
 Feverb
  Yes36 (10.3)32 (12.2)4 (4.6)
  No314 (89.7)231 (87.8)83 (95.4)
Study visits and outcome
 Initial serum creatinine, mg/dl, median (IQR)0.81 (0.70–0.90)0.84 (0.77–0.94)0.63 (0.57–0.68)
 Final serum creatinine, mg/dl, median (IQR)0.81 (0.70–0.90)0.91 (0.80–1.03)0.64 (0.57–0.72)
 Initial cystatin C, mg/L, median (IQR)0.82 (0.74–0.92)0.85 (0.77–0.95)0.72 (0.67–0.80)
 Final cystatin C, mg/L, median (IQR)0.84 (0.76–0.94)0.88 (0.80–1.01)0.72 (0.67–0.80)
 Initial eGFR, ml/min per 1.73 m2, median (IQR)118.3 (106.6–125.4)116.2 (102.4–124.6)122.0 (116.3–127.2)
 Final eGFR, ml/min per 1.73 m2, median (IQR)113.1 (99.4–122.3)110.4 (92.5–120.1)120.2 (110.6–126.6)
  • eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation on the basis of creatinine and cystatin c. Questionnaire data before recoding are presented in Supplemental Table 1. IQR, interquartile range. NSAID, nonsteroidal anti-inflammatory drug; UTI, diagnosed with a urinary tract infection typically without microbiologic or dipstick confirmation.aOther occupations include teacher, painter, shoemaker, security, manufacturing operator, and barber.

  • b Over the last 6 months.

  • c Over the last week.

  • d Data were collected at the second visit.