Introduction
Materials and methods
Study design and study area
Study participants
Data collection
Interview with a structured questionnaire
Personal particulate matter monitoring
Heart rate and heart rate variability measurement
Ethical clearance
Statistical procedures
Results
Sociodemographic and health characteristics of study participant
Variable | Total (N = 207) | E-waste Workers (N = 142) | Comparable group (N = 65) | P-value |
Age in years: mean ± SD | 27.87 ± 8.14 | 26.45 ± 6.74 | 30.97 ± 9.92 | < 0.001 |
Education (%) | < 0.001 | |||
None | 45(22.96) | 39(27.86) | 6(10.71) | |
Primary | 42(21.43) | 38(27.14)) | 4(7.14) | |
Middle/JHS | 61(31.12) | 44(31.43) | 17(30.36) | |
Secondary/SHS+ | 48(24.49) | 19(12.86) | 29(31.29) | |
Marital Status | 0.05 | |||
Single | 74(49.0) | 44(45.4) | 30(58.8) | |
Married | 74(49.0) | 53(54.6) | 21(41.2) | |
Daily Income (%)* | < 0.001 | |||
≤ GHS 20 | 36(18.00) | 26(18.44) | 10(16.95) | |
GHS 20–40 | 59(29.5) | 46(32.62) | 13(22.03) | |
GHS 41–60 | 57(28.5) | 38(26.95) | 19(32.2) | |
GHS 61+ | 48(24.0) | 31(20.91) | 16(3.28) | |
Indoor cooking (%) | 45(22.73) | 22(15.94) | 23(38.33) | < 0.001 |
Lifestyle habits (%) | ||||
Alcohol use (%) | 0.181 | |||
Current | 24(11.94) | 19(13.48) | 5(8.33) | |
Previous | 7(3.48) | 3(2.13) | 4(6.67) | |
Never | 170(84.58) | 119(84.40) | 51(85.00) | |
Cigarette smoking (%) | 0.001 | |||
Current | 50(25.13) | 27(41) | 6(10) | |
Never | 149(74.87) | 96.2(111) | 54(90) | |
4-h personal air weather variables | ||||
Relative humidity (%) | 57.59 ± 7.32 | 56.13 ± 5.51 | 60.91 ± 9.55 | 0.229 |
Barometric pressure (mmHg) | 7410.79 ± 63.40 | 7512.89 ± 33.6 | 7170 ± 105.09 | 0.037 |
Ambient temperature (°C) | 36.49 ± 2.84 | 37.15 ± 2.21 | 35.00 ± 3.49 | < 0.001 |
Self-reported medical History (%) | ||||
Pulmonary Tuberculosis | 2(1) | 2(1.42) | 0(0) | 0.86 |
Bronchial Asthma | 7(3.48) | 5(3.55) | 2(3.33) | 0.010 |
Hypertension | 0.001 | |||
Yes | 11(9.3) | 15.2(12) | 8(19.1) | |
No | 90(76.3) | 84.6(66) | 33(78.6) | |
Diabetes Mellitus | 0.005 | |||
Yes | 5(4.3) | 2.6(2) | 4(9.5) | |
No | 91(78.5) | 97.4(75) | 36(85.7) | |
Dyslipidaemia | 0.000 | |||
Yes | 5(4.3) | 2.6(2) | 5(11.9) | |
No | 89(76.1) | 94.9(74) | 35(83.3) | |
Don’t know | 23(19.7) | 2.6(2) | 2(4.8) | |
Medications (%) | ||||
Anti-hypertensive | 0.730 | |||
Yes | 7(18.4) | 5(20) | 2(15.4) | |
No | 31(81.6) | 20(80) | 11(84.6) | |
Anti-diabetes | 0.540 | |||
Yes | 2(5.7) | 1(4.2) | 1(9.1) | |
No | 33(94.3) | 23(95.8) | 10(90.9) | |
Statins | ||||
Yes | 2(6.1) | 2(8.7) | 0(0) | 1.000 |
No | 31(93.9) | 21(91.3) | 10(100) | |
Total | E-waste (n = 100) | Comparable group (n = 42) | P-value | |
BMI (kg/m2): mean ± SD | 23.37 ± 3.19 | 23.19 ± 3.05 | 23.75 ± 3.44 | 0.100 |
BMI category (n, %) | ||||
Normal - BM1 18-25 kg/m2, (n, %) | 161(77.8) | 117(83.39) | 44 (67.69) | 0.404 |
Abnormal - BMI > 25 kg/m2(n, %) | 46 (22.22) | 25(17.61) | 25 (32.31) | 0.113 |
Blood pressure (mmHg): mean ± SD | ||||
Systolic blood pressure | 124.34 ± 15.52 | 122.31 ± 12.62 | 128.84 ± 17.58 | 0.010 |
Diastolic blood pressure | 74.13 ± 10.42 | 73.15 ± 9.31 | 75.98 ± 12.55 | 0.110 |
High Blood pressure category (n, %) | ||||
Normal | 129(62.6) | 94(66.2) | 35(54.7) | 0.198 |
Elevated | 32(15.5) | 14(21.9) | 18(12.7) | |
Stage 1 | 28(13.6) | 11(17.2) | 17(12) | |
Stage 2 | 17(8.3) | 4(6.3) | 13(9.2) | |
Resting pulse rate (bpm): mean ± SD | 74.1 ± 12.1 | 74.2 ± 12.6 | 74.1 ± 13.6 | 0.960 |
Resting pulse rate category (n, %) | ||||
< 85 bpm (Normal) | 157(75.85) | 107(75.35) | 50(76.92) | 0.806 |
≥ 85 bpm (Abnormal) | 50(24.15) | 35(24.65) | 15(23.08) | |
Blood oxygen saturation (%): mean ± SD | 96.56 ± 3.23 | 96.34 ± 3.64 | 97.06 ± 1.94 | 0.019 |
Blood oxygen saturation category (n, %) | ||||
≥ 95% (Normal) | 94.7 (195) | 93.7 (133) | 96.9 (62) | 0.343 |
< 95% (Abnormal) | 11(5.3) | 9(6.3) | 2(3.1) | |
Heart rate variability (Mean ± SD) | ||||
Log LF | 10.4 ± 1.73 | 11.1 ± 0.74 | 10.0 ± 2.01 | ≤0.001 |
Log HF | 9.8 ± 2.03 | 9.2 ± 2.20 | 10.8 ± 0.92 | ≤0.001 |
LH/ HF ratio | 2.4 ± 2.23 | 2.8 ± 2.32 | 1.8 ± 1.40 | 0.004 |
Log SDNN | 5.43 ± 0.61 | 5.2 ± 0.71 | 5.8 ± 3.02 | ≤0.001 |
Log RMSSD | 5.21 ± 0.81 | 4.9 ± 0.81 | 5.7 ± 0.30 | ≤0.001 |
MeanNN | 5.82 ± 1.91 | 5.9 ± 0.33 | 6.4 ± 0.21 | ≤0.001 |
Variations in particulate matter concentrations in personal air of study participants
Variations in heart rate variability indices, and resting heart rate among study participants
Variable | E-waste –workers (n = 142) | Comparable group (n = 65) | p-value |
---|---|---|---|
5-min resting Heart Rate Variability, Mean (SD) | |||
RI (Dry season) | |||
Mean NN | 5.97 ± 0.31 | 6.35 ± 0.21 | ≤ 0.001 |
Log SDNN | 4.23 ± 0.68 | 5.88 ± 0.08 | ≤ 0.001 |
Log RMSSD | 4.88 ± 0.84 | 5.72 ± 0.30 | ≤ 0.001 |
Log LF | 9.98 ± 1.98 | 11.12 ± 0.68 | ≤ 0.001 |
Log HF | 9.25 ± 2.25 | 10.77 ± 0.91 | ≤ 0.001 |
LF/HF ratio | 2.75 ± 2.33 | 1.84 ± 1.66 | 0.004 |
R II (Rainy season) | |||
Mean NN | 6.01 ± 0.29 | 6.24 ± 0.30 | ≤ 0.001 |
Log SDNN | 5.28 ± 0.67 | 5.60 ± 0.55 | ≤ 0.001 |
Log RMSSD | 4.85 ± 0.93 | 5.48 ± 0.74 | ≤ 0.001 |
Log LF | 10.00 ± 2.07 | 10.71 ± 1.53 | 0.030 |
Log HF | 9.19 ± 2.49 | 10.28 ± 1.83 | 0.010 |
LF/HF ratio | 3.50 ± 5.12 | 1.85 ± 1.31 | 0.010 |
R III (Harmattan season) | |||
Mean NN | 5.89 ± 0.26 | 5.91 ± 0.84 | 0.841 |
Log SDNN (ms) | 5.02 ± 0.82 | 5.34 ± 0.67 | 0.030 |
Log RMSSD (ms) | 4.55 ± 0.94 | 5.05 ± 0.83 | 0.010 |
Log LF (ms2) | 9.36 ± 2.38 | 10.22 ± 1.71 | 0.030 |
Log HF (m/s) | 8.45 ± 2.57 | 9.57 ± 2.06 | 0.010 |
LF/HF ratio | 3.60 ± 2.93 | 2.46 ± 1.81 | 0.010 |
Heart rate (beats/min), Mean (SD) | |||
Round I | 73.91 ± 10.16 | 74.09 ± 13.63 | 0.960 |
Round II | 70.16 ± 10.64 | 69.52 ± 10.54 | 0.050 |
Round III | 73.91 ± 10.16 | 74.00 ± 12.67 | 0.960 |
Association between particulate matter exposure and heart rate variability indices
Variable | Crude | Adjusted | ||
---|---|---|---|---|
Heart rate variability | β[95% CI] | P-value | β [95% CI] | P-value |
MeanNN | ||||
PM2.5 | −0.54(− 0.99, − 0.097) | 0.017 | − 0.76(− 1.48, − 0.04) | 0.039 |
PM10–2.5 | 0.01(− 0.12,0.12) | 0.989 | 0.14(− 0.08,0.25) | 0.218 |
PM10 | 0.05(− 0.09,0.19) | 0.448 | 0.05(− 0.14,0.25) | 0.591 |
SDNN | ||||
PM2.5 | − 0.35(− 0.71,0.01) | 0.059 | 0.34(− 1.32,0.64) | 0.493 |
PM10–2.5 | 0.63(0.11,1.13) | 0.017 | −0.11(− 1.73,0.95) | 0.846 |
PM10 | −0.52-0.95, − 0.93) | 0.017 | − 0.34(− 1.32,0.64) | 0.035 |
RMSSD | ||||
PM2.5 | 0. 49(− 0.86,0.33) | ≤0.001 | −0.27(−1.34,0.79) | 0.620 |
PM10–2.5 | 0.93(− 0.41,1.46) | ≤0.001 | − 0.01(−1.26,1.28) | 0.275 |
PM10 | −0.77(− 0.86, − 1.24) | 0.009 | − 0.57(− 1.56,0.46) | 0.255 |
LF | ||||
PM2.5 | −0.002(− 0.009,0.004) | 0.507 | − 0.007(− 0.004,0.023) | 0.154 |
PM10–2.5 | 0.003(− 0.006,0.012) | 0.552 | − 0.006(− 0.101,0.002) | 0.479 |
PM10 | 0.002(− 0.006,0.012) | 0.533 | − 0.004(− 0.021,0.010) | 0.213 |
HF | ||||
PM2.5 | 0.002(−0.005,0.010) | 0.521 | 0.010(−0.005,0.025) | 0.199 |
PM10–2.5 | 0.001(−0.002,0.002) | 0.903 | −0.004(− 0.009,0.001) | 0.107 |
PM10 | −0.001(− 0.004,0.001) | 0.310 | − 0.005(− 0.012,0.001) | 0.104 |
LF/HF | ||||
PM2.5 | 0.008(−0.002, 0.019) | 0.117 | 0.020(−0.256,0.301 | 0.867 |
PM10–2.5 | 0.013(0.001, −0.245) | 0.035 | 0.004(−0.402–0.032) | 0.030 |
PM10 | 0.015(− 0.029–0.011) | 0.035 | 0.003(−0.273–0.034) | 0.836 |
HR (beats/min) | ||||
PM2.5 | 0.014(−0.023, 0.051) | 0.462 | 0.066(−0.015,0.147) | 0.110 |
PM10–2.5 | 0.001(−0.007,0.009) | 0.862 | −0.001(− 0.027,0.025) | 0.932 |
PM10 | 0.002(−0.013,0.009) | 0.742 | −0.010 (− 0.040,0.020) | 0.522 |