Spirometric reference equations for Cameroonians aged 4 to 89 years derived using lambda, mu, sigma (LMS) method.

Area of Science:

• Pulmonary Medicine
• Respiratory Physiology
• Public Health

Background:

• Normative spirometric values are established for many ethnic groups, but data for Black Africans are limited.
• Accurate spirometry interpretation relies on population-specific reference equations.
• Previous studies have not adequately assessed spirometric values in Cameroonian children and adults.

Purpose of the Study:

• To establish normative spirometric reference equations for Cameroonian children and adults.
• To compare these new equations with existing Global Lung Initiative (GLI) and Nigerian standards.
• To improve the accuracy of spirometry interpretation within the Cameroonian population.

Main Methods:

• Spirometric data were collected from 625 children and 1152 adults in Cameroon between 2014 and 2018.
• Reference equations were derived using a generalized additive model (GAM) for location, shape, and scale.
• The prediction equation format is: M = Exp[a0 + a1*ln(Height) + a2*ln(Age) + Mspline], where Mspline accounts for age-related variations.

Main Results:

• Cameroonian children and adolescents showed spirometric values (FEV1, FVC) close to GLI standards for African Americans.
• Cameroonian adults exhibited significantly lower FEV1 and FVC compared to GLI standards for African Americans.
• The FEV1/FVC ratio in Cameroonian adults was similar to Nigerian standards for males but lower for females.

Conclusions:

• Cameroonian children's lung function (FEV1, FVC) closely aligns with Black American reference values.
• Cameroonian adults' lung function (FEV1, FVC) is notably lower than that of Black American adults.
• The derived Cameroonian spirometric equations are essential for accurate pulmonary function assessment in this population.