Supplementary file 1_Quantile regression application to identify key determinants of malnutrition in five West African countries of Gabon, Gambia, Liberia, Mauritania, and Nigeria.docx

BackgroundMalnutrition remains one of the most pressing health challenges, particularly in developing nations across Africa, placing a significant burden on both public health agencies and the affected countries. In countries such as Gabon, Gambia, Mauritania, Liberia, and Nigeria, the burden of malnutrition exacerbates public health systems, strains economic resources, and hinders sustainable development, underscoring the urgent need for coordinated efforts at national and international levels. This study aimed to determine the scope and underlying factors contributing to the elevated incidence of malnutrition in West African countries, specifically Gabon, Gambia, Liberia, Mauritania, and Nigeria.
MethodThis study employed a quantile regression model to examine the determinants of malnutrition at various quantiles of interest across the Western African countries under consideration to facilitate focused policy measures and intervention strategies aimed at decreasing the prevalence.
ResultsFor the lower quantiles (0.1 and 0.25), which indicate severe malnutrition, significant variables included the child’s weight [quantile = 0.1, 95% CI(0.0063, 0.0103), quantile = 0.25, 95% CI(0.0054, 0.0107)], mother’s education level [No education: quantile = 0.1, 95% CI(−49.7471, −32.1376), quantile = 0.25, 95% CI(−38.1513, −22.4438) Primary: quantile = 0.1, 95% CI(−24.8095, −5.7693), quantile = 0.25, 95% CI(−19.5273, −6.3424) Higher: quantile = 0.1, 95% CI(5.6499, 40.3274), quantile = 0.25, 95% CI(21.8158, 40.278)], drinking water source [Natural Sources: quantile = 0.1, 95% CI(0.6877, 24.384),Piped: quantile = 0.1, 95% CI(25.578, 45.2368), quantile = 0.25, 95% CI(22.2782, 34.8212), Bottle/Sachet: quantile = 0.25, 95% CI(3.438, 98.1675)], toilet type [Flush: quantile = 0.25, 95% CI(2.2598, 18.3457),Other: quantile = 0.1, 95% CI(8.7863, 24.504), quantile = 0.25, 95% CI(7.0995, 20.1119)], household wealth index [Poorest: quantile = 0.1, 95% CI(−52.5112, −16.9197), quantile = 0.25, 95% CI(−48.3804, −23.0633),Poorer: quantile = 0.1, 95% CI(−38.8744, −4.7586), quantile = 0.25, 95% CI(−34.6993, −9.1766), Middle: quantile = 0.25, 95% CI(−28.9491, −6.5834)], health care visits [No: quantile = 0.1, 95% CI(−19.293, −3.6393), quantile = 0.25, 95% CI(−17.2342, −5.6411)], consumption of fortified foods and tubers [No: quantile = 0.1, 95% CI(−36.3898, −12.0378), quantile = 0.25, 95% CI(−17.8127, −1.2374)], anemia status [Anemic: quantile = 0.1, 95% CI(−15.9326, −1.1929), quantile = 0.25, 95% CI(−12.3361, −1.5516)], mosquito net usage [No: quantile = 0.1, 95% CI(−22.0323, −0.8033), quantile = 0.25, 95% CI(−13.8107, 1.1366)], child’s age [0 to 12 months: quantile = 0.1, 95% CI(81.6424, 105.7155), quantile = 0.25, 95% CI(61.4817, 78.5194),12 to 24 months: quantile = 0.1, 95% CI(0.5592, 24.933), 24 to 36 months: quantile = 0.1, 95% CI(7.9128, 40.2828)] and gender [Female: quantile = 0.1, 95% CI(4.5351, 17.9783), quantile = 0.25, 95% CI(5.0076, 15.4735)], and recent fever [No: quantile = 0.1, 95% CI(11.5663, 29.5984), quantile = 0.25, 95% CI(7.0313, 20.8918)]. Residence type was significant for the 0.25 quantile but not the 0.1 quantile [Rural: quantile = 0.25, 95% CI(−14.7051, −2.1455)]. At higher quantiles (0.75, 0.85, 0.9, and 0.95), factors such as the use of mosquito nets, formula feeding, and access to piped water remain significant, while socioeconomic determinants like maternal education and wealth index lose their influence. Common variables across all quantiles were mother’s age, child’s age (0 to 12 months), child’s gender, and recent fever.
ConclusionThese findings underscore the critical role of primary health care interventions in identifying and managing malnutrition, particularly among lower quantiles where severe malnutrition dominates. High-risk groups, such as teenagers and low-income mothers, should receive targeted support, including prenatal classes and counseling. Community caregivers can monitor at-risk individuals and ensure timely referrals, while collaborations with nonprofits can improve access to food and supplements. Promoting community food gardens, clean water access, and public workshops can further aid prevention and education efforts.

背景：营养不良仍是全球最紧迫的公共卫生挑战之一，在非洲发展中国家尤为突出，给公共卫生机构与受影响国家均带来了沉重负担。在加蓬、冈比亚、毛里塔尼亚、利比里亚及尼日利亚等国，营养不良负担进一步加剧公共卫生系统压力、消耗经济资源并阻碍可持续发展，凸显出在国家与国际层面开展协同应对的迫切性。本研究旨在明确西非国家（具体为加蓬、冈比亚、利比里亚、毛里塔尼亚与尼日利亚）营养不良发病率升高的影响范围与潜在成因。
方法：本研究采用分位数回归模型（quantile regression model），对目标西非国家不同关注分位数下的营养不良影响因素展开分析，以期为制定针对性政策措施与干预策略以降低营养不良患病率提供依据。
结果：针对代表重度营养不良的低分位数（0.1与0.25分位数），具有显著影响的变量包括：儿童体重[0.1分位数：95%置信区间（CI）(0.0063, 0.0103)；0.25分位数：95%置信区间(0.0054, 0.0107)]、母亲受教育水平[未受教育：0.1分位数：95%置信区间(−49.7471, −32.1376)，0.25分位数：95%置信区间(−38.1513, −22.4438)；小学教育：0.1分位数：95%置信区间(−24.8095, −5.7693)，0.25分位数：95%置信区间(−19.5273, −6.3424)；高等教育：0.1分位数：95%置信区间(5.6499, 40.3274)，0.25分位数：95%置信区间(21.8158, 40.278)]、饮用水源[自然水源：0.1分位数：95%置信区间(0.6877, 24.384)；管道供水：0.1分位数：95%置信区间(25.578, 45.2368)，0.25分位数：95%置信区间(22.2782, 34.8212)；瓶装/袋装水：0.25分位数：95%置信区间(3.438, 98.1675)]、厕所类型[冲水厕所：0.25分位数：95%置信区间(2.2598, 18.3457)；其他厕所：0.1分位数：95%置信区间(8.7863, 24.504)，0.25分位数：95%置信区间(7.0995, 20.1119)]、家庭财富指数[最贫困阶层：0.1分位数：95%置信区间(−52.5112, −16.9197)，0.25分位数：95%置信区间(−48.3804, −23.0633)；较贫困阶层：0.1分位数：95%置信区间(−38.8744, −4.7586)，0.25分位数：95%置信区间(−34.6993, −9.1766)；中等阶层：0.25分位数：95%置信区间(−28.9491, −6.5834)]、就医情况[未就医：0.1分位数：95%置信区间(−19.293, −3.6393)，0.25分位数：95%置信区间(−17.2342, −5.6411)]、强化食品与块根类食物摄入[未摄入：0.1分位数：95%置信区间(−36.3898, −12.0378)，0.25分位数：95%置信区间(−17.8127, −1.2374)]、贫血状态[贫血：0.1分位数：95%置信区间(−15.9326, −1.1929)，0.25分位数：95%置信区间(−12.3361, −1.5516)]、蚊帐使用情况[未使用：0.1分位数：95%置信区间(−22.0323, −0.8033)，0.25分位数：95%置信区间(−13.8107, 1.1366)]、儿童年龄[0~12月龄：0.1分位数：95%置信区间(81.6424, 105.7155)，0.25分位数：95%置信区间(61.4817, 78.5194)；12~24月龄：0.1分位数：95%置信区间(0.5592, 24.933)；24~36月龄：0.1分位数：95%置信区间(7.9128, 40.2828)]、儿童性别[女性：0.1分位数：95%置信区间(4.5351, 17.9783)，0.25分位数：95%置信区间(5.0076, 15.4735)]以及近期发热情况[未发热：0.1分位数：95%置信区间(11.5663, 29.5984)，0.25分位数：95%置信区间(7.0313, 20.8918)]。居住类型仅在0.25分位数下具有显著影响，0.1分位数下无显著影响[农村地区：0.25分位数：95%置信区间(−14.7051, −2.1455)]。在高分位数（0.75、0.85、0.9及0.95分位数）下，蚊帐使用、配方奶喂养与管道供水获取等因素仍具有显著影响，而母亲受教育水平与家庭财富指数等社会经济决定因素则不再具有显著影响。所有分位数下均具有显著影响的变量包括母亲年龄、儿童年龄（0~12月龄）、儿童性别以及近期发热情况。
结论：本研究结果凸显了初级卫生保健干预在识别与管理营养不良方面的关键作用，尤其是在重度营养不良占比更高的低分位数群体中。青少年与低收入母亲等高危群体应获得针对性支持，包括产前课程与健康咨询。社区照护人员可对高危个体进行监测并确保及时转诊，而与非营利组织的合作则可提升食物与营养补充剂的可及性。推广社区菜园建设、清洁饮用水获取渠道以及公共宣讲活动，可进一步助力营养不良的预防与健康教育工作。