Respiratory Symptoms and Ventilatory Function Impairment Among Wood Workers in the Savannah Belt of Northern Nigeria

Background: Exposure to wood dust and substances connected to wood processing have been associated with a variety of health hazzards. Both upper and lower respiratory tract diseaes have been noticed and described. Several publications are found in the literature on these but no such report has come from the Savannah belt with its peculiar climatic conditions.
Methods: One hundred and forty (140) workers in a wood furniture factory in Kaduna, a city within the Savannah belt of Northern Nigeria, were studied for presence of respiratory symptoms and /or ventilatory function impairment using the MRC questionnaire on respiratory symptoms and an electronic Spirometer. The workers were classified into five working groups according to their nature of work in the factory, such as Machine shop, Assembling, Spray room, Upholstery and Administration.
Results: Forty eight (48) out of the one hundred and forty (140) workers (34.3%) had respiratory symptoms. Prevalent symptoms identified were chronic cough, corrhiza, breathlessness and wheeze. The workers in the machine shop and the spray room had higher prevalence of respiratory symptoms of 60.5% (p<0.001) and 54.9% (p<0.001) respectively. The other groups of workers within the company did not have significant symptoms. The prevalence of symptoms increased with increasing years of exposure in the same group of workers, from 10% among workers with less than 5 years exposure to 93% among those who had worked for over 19 years in the Machine shop. A similar pattern was seen among the Spray room workers, rising from 10% in workers with less than 5 years exposure to 65% in workers with over 19 years exposure. Forced expiratory volume in one second (FEV₁), Forced vital capacity (FVC) and Peak expiratory flow rate (PEFR) were significantly reduced among workers in the machine shop and the Spray room. Significant obstructive pattern of impairment in FEV₁, FVC and PEFR were recorded among workers in the Machine shop (p<0.05) and the spray room (p<0.05) but not in the other groups of workers . There was significant reversal of airway obstruction, following inhalation of 200ug of salbutamol aerosols with improvement in PEFR greater than 15%.
Conclusion: We conclude that respiratory symptoms are highly prevalent and ventilatory functions also impaired among wood workers in the savannah belt.