Figure 1
Sampling Scheme.
Table 1
Socio-Demographic Characteristics Between Three Study Groups.
| DEMOGRAPHY | CEMENT-EXPOSED N = 100 | INDOOR UNEXPOSED N = 50 | OUTDOOR UNEXPOSED N = 50 |
|---|---|---|---|
| Age in years (Mean, SD) | 40.1 (11.4) | 33.9 (12.1) | 33.6 (10.9) |
| Religion, n (%) | |||
| Muslim | 71 (71) | 36 (72) | 21 (42) |
| Non-Muslim | 29 (29) | 14 (28) | 29 (58) |
| Caste, n (%) | |||
| Non-general | 24 (24) | 22 (44) | 35 (70) |
| General | 64 (64) | 28 (56) | 15 (30) |
| Do not want to tell | 12 (12) | 0 | 0 |
| Education, n (%) | |||
| No schooling | 62 (62) | 13 (26) | 17 (34) |
| Primary | 22 (22) | 19 (38) | 16 (32) |
| Middle & Senior secondary | 15 (15) | 15 (30) | 16 (32) |
| Graduate and above | 1 (1) | 3 (6) | 1 (2) |
| Literacy (Read or Write) | 43 (43) | 43 (86) | 36 (72) |
| Married, n (%) | 96 (96) | 37 (74) | 39 (78) |
| Living with Spouse | 28 (29.2) | 12 (32.4) | 17 (43.6) |
| Living with, n (%) | |||
| Alone | 33 (33) | 6 (12) | 5 (10) |
| Co-workers | 43 (43) | 28 (56) | 20 (40) |
| Family only | 23 (23) | 16 (32) | 24 (48 |
| Family & other co-workers | 1 (1) | 0 | 1 (2) |
| Monthly income, n (%) | |||
| <=10000 ₹ | 70 (70) | 31 (62) | 29 (58) |
| 10001₹–25000₹ | 30 (30) | 18 (36) | 21 (42) |
| Missing | 0 | 1 (2) | 0 |
| Household size (Median/IQR) | 4 (1,5) | 4.5 (3,5) | 4 (3,6) |
| Electricity, n (%) | 91 (91) | 50 (100) | 49 (98) |
| Metered, n (%) | 7 (7.7) | 48 (96) | 49 (100) |
| Type of household, n (%) | |||
| Kuccha | 97 (97) | 1 (2) | 1 (2) |
| Semi Pucca | 0 | 0 | 3 (6) |
| Pucca | 3 (3) | 49 (98) | 46 (92) |
| Running water inside house, n (%) | 5 (5) | 47 (94) | 45 (90) |
| Latrine, n (%) | |||
| Open fields | 4 (4) | 0 | 0 |
| Public place | 89 (89) | 0 | 1 (2) |
| Common | 4 (4) | 35 (70) | 36 (72) |
| Inside house | 3 (3) | 15 (30) | 13 (26) |
| Cooking done, n (%) | |||
| Outdoors | 3 (3) | 1 (2) | 2 (4) |
| Inside house | 92 (92) | 47 (94) | 47 (94) |
| In a separate building | 5 (5) | 2 (4) | 1 (2) |
| Fuel used for cooking, n (%) | |||
| Bio | 18 (18) | 0 | 1 (2) |
| LPG | 82 (82) | 50 (100) | 49 (98) |
| SES score* (Mean, SD) | 3.18 (1.43) | 4 (1.43) | 4.52 (1.94) |
| BMI (Mean, SD) | 23.2 (3.1) | 22.8 (3.9) | 22.9 (3.2) |
| Blood pressure (mm/hg) | |||
| Systolic (Mean, SD) | 138.6 (16.9) | 140.5 (20.7) | 137.2 (17.4) |
| Diastolic (Mean, SD) | 85.5 (12.1) | 83.3 (13.2) | 81 (11.4) |
[i] * SES score is a composite of Literacy, Income, Fuel, Cycle, Motor, TV, Cable, Mobile, and Mobile Expenditure.
Table 2
Comparison of Lung Function Between the Three Groups.
| LUNG FUNCTION PARAMETERS | CEMENT EXPOSED N = 100 | INDOOR UNEXPOSED N = 50 | OUTDOOR UNEXPOSED N = 50 |
|---|---|---|---|
| FVC (Mean, SD) | 3.3 (0.7) | 3.4 (0.6) | 3.6 (0.6) |
| FEV1 (Mean, SD) | 2.5 (0.6) | 2.8 (0.6) | 2.9 (0.6) |
| PEF (Mean, SD) | 5.5 (1.7) | 6.6 (1.7) | 6.8 (1.7) |
| FEV1/FVC (%) (Mean, SD) | 74.5 (8.7) | 80.5 (6.9) | 79.2 (8.9) |
| FEV1/FVC (%) < 70% N (%) | 19 (20.2) | 3 (6.3) | 5 (10.6) |
| FEV1 % <80% of predicted FEV1% N (%) | 67 (71.3) | 31 (64.6) | 26 (55.3) |
[i] * Normal FEV1/FVC (%) ratio should be at least is 70%.
** Normal value of FEV1% is more than or equal to 80%.
Table 3
Association of Cement Exposure with Lung Function and Respiratory Morbidity.
| OUTCOMES | GROUPS | MEAN DIFFERENCE (95% CI), P VALUE | |
|---|---|---|---|
| UNADJUSTED MD | ADJUSTED MD* | ||
| FVC (Liters) | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 0.17 (–0.09, 0.44) –0.14 (–0.37, 0.08) 0.02 | 1 0.16 (–0.09, 0.40) 0.06 (–0.16, 0.28) 0.45 |
| FEV1 (Liters in 1 second) | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 0.09 (–0.15, 0.34) –0.30 (–0.51, –0.09) <0.001 | 1 0.07 (–0.15, 0.29) –0.09 (–0.28, 0.11) 0.33 |
| PEF (Liters/sec) | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 0.18 (–0.51, 0.87) –1.11 (–1.70, –0.52) <0.001 | 1 0.58 (–0.62, 0.74) –0.75 (–1.36, –0.15) 0.01 |
| FEV1/FVC (%) | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 –1.35(–4.73, 2.02) –5.99 (–8.91, –3.08) <0.001 | 1 –1.75 (–5.05, 1.54) –3.87 (–6.77, –0.96) 0.03 |
| RATE RATIO** (95% CI), P VALUE | |||
| Respiratory symptom score (0–13) | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 1.13 (0.69, 1.85) 2.41 (1.57, 3.70) <0.001 | 1 1.11 (0.69, 1.79) 2.45 (1.63, 3.69) <0.001 |
| ODDS RATIO (95% CI), P VALUE | |||
| FEV1/FVC (%) <70% | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 1.79 (0.40, 7.94) 3.80 (1.06, 13.57) 0.07 | 1 2.31 (0.47, 11.32) 2.51 (0.64, 9.84) 0.41 |
| FEV1 <80% of PredFEV1 | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 0.68 (0.30, 1.55) 1.36 (0.65, 2.86) 0.17 | 1 0.62 (0.26, 1.51) 0.95 (0.43, 2.12) 0.50 |
| Any respiratory symptoms | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 1.27 (0.58, 2.78) 7.21 (3.26, 15.93) <0.001 | 1 1.38 (0.60, 3.16) 7.38 (3.21, 17.00) <0.001 |
| Any high-grade respiratory symptoms | Indoor un-exposed Outdoor un-exposed Cement-exposed | 1 1 (0.36, 2.66) 3.55 (1.60, 7.87) <0.001 | 1 1.13 (0.41, 3.10) 3.46 (1.49, 8.00) 0.003 |
[i] * Adjusted for age, BMI, smoking, SES, and years of exposure.
** Zero-inflated Negative Binomial Regression.
*** R2 for exposure to PEF = 0.04 and FEV1/FVC (%) = 0.03.
Figure 2
Prevalence of Respiratory Symptoms in the Three Study Groups.
Table 4
Comparison of lung functions and respiratory symptoms between exposed to cement vs. controls from previous literature.
| AUTHOR, YEAR COUNTRY | EXPOSED | TYPE OF CONTROLS | UNADJUSTED DIFFERENCE BETWEEN EXPOSED AND UN-EXPOSED | UNADJUSTED DIFFERENCE IN SYMPTOM PERCENTAGE BETWEEN EXPOSED AND UN-EXPOSED | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FVC ML | FEV1 ML | PEF ML/SEC | FEV1/FVC (%) | COUGH (%) | PHLEGM (%) | DYSPNEA (%) | WHEEZING (%) | |||
| Present study | Informal workers exposed to cement | Indoor tailors Outdoor vegetable sellers | –100 –300 | –300 –400 | –1100 –1300 | –6 –4.7 | 35 33 | 18 18 | 12 11 | 27 23 |
| Aweto, 2018 Nigeria [7] | Cement factory workers | Civil servants | –940 | –830 | –1060 | –3.73 | – | – | – | – |
| Tungu, 2014 Tanzania [12] | Cement factory workers | In 2002 Maintenance and administrationIn 2010 Mineral water production workers | –200 –80 | –400 –100 | – – | –10 –1 | 13.7 6 | 23.9 3.7 | 12.7 4.3 | 8.8 3.7 |
| Tungu, 2015 Tanzania [27] | Cement production workers | Mineral water production workers | 5 | 6 | 6 | –1 | ||||
| Al-Neaimi, 2001 United Arab Emirates [5] | Factory supervisors, factory attendants, maintenance workers, machine operators | Workers attending the preventive medicine clinic to acquire a certificate of good health | –250 | –400 | –2560 | –5.86 | 24.3 | 25.7 | 32.9 | – |
| Rachiotis, 2018 Greece [10] | Cement production workers | White collar employees outside factory | % predicted +1 | % predicted –1.5 | – | –1.5 | – | – | – | – |
| Ismaila, 2015 Nigeria [25] | Workers in cement production section | Workers in administrative section of factory | – | – | Given for combined 6.1l/s | – | – | – | – | – |
| Rafeemanesh, 2015 Iran [11] | High exposed workers from production and packing sections | Workers of the same factory without current and past exposure | % predicted –1.9 | % predicted –2.7 | – | –1 | 5 | 6 | 4 | 0 |
| Aminian, 2014 Iran [6] | High exposed workers from production and packing sections | Less exposed office workers Pre-shift Post-shift | +210 +90 | +190 +60 | +170 +490 | +0.45 +0.17 | – – | – – | – – | – – |
| Meo, 2013 Pakistan[24] | Non-smoking cement mill workers | Clerical staff, shopkeepers, and salesmen <5 work experience >5 to <10 >10 | –850 –1160 –740 | –490 –630 –460 | –738 –583 –1366 | +5.7 +9.5 –4.3 | – –– | – –– | – –– | – –– |
| Kakooei, 2012 Iran [8] | Male cement production line workers | Administrative sectionemployees. | –310 | –310 | – | –3 | 17.8 | 12 | 12.2 | 15.4 |
| Zeleke, 2011 Ethiopia [26]2009 | Cement factory cleaners and production workers | Security workers from both factories 2009 Cleaners vs. production Cleaners vs. control Production vs. controls 2010 Cleaners vs. production Cleaners vs. control Production vs. controls | +230 +210 –20 +220 +210 –10 | +230 +130 –100 +170 +60 –110 | – – – – – – | +1.02 –1.13 –2.15 +1.13 –2.34 –3.47 | – – – – – – | – – – – – – | 4.4 10.5 6.1 2.6 2.6 0 | –0.5 18.7 19.2 13 34.2 21.2 |
| Mbelambela, 2018 Kongo central province [9] | Cement factory workers (transportation, cleaning and production) | Less exposed- Administration, laboratory | – | – | – | – | 13.3 | 8.5 | 2.5 | 2.2 |
| Thepaksorn, 2013 Thailand [14] | Male roofing cement workers | Office workers (n=19) and subcontract workers | – | – | – | – | 5.5 | 9.6 | 6.7 | |
| Ahmed, 2012 United Arab Emirates [13] | Workers exposed to cement dust | 74 subjects not exposed to dust, from administration, finance and other department | – | – | – | – | 14.4 | 13.5 | 6.9 | –0.6 |