The association between leptin and inflammatory markers with obesity indices in Zanzibari children, adolescents, and adults

Background: Research from Western populations describes abdominal obesity as a low-grade inflammatory disease; less is known from tropical areas with high pathogen burden.

Objectives: This cross-sectional study investigated whether obesity contributes to low-grade inflammation in 587 individuals from randomly selected households in Zanzibar.

Materials and methods: The Association between obesity indices (body mass index [BMI], waist circumference [WC], and percentage body fat [%BF]), leptin, and inflammatory markers (C-reactive protein [CRP], interleukin-6 [IL-6] and tumor-necrosis factor-α [TNF-α]) was investigated using multinomial logistic regression analysis, accounting for ordinal outcome variables with four categories; 1st-4th quartile.

Results: Study participants were between 5 and 95 years; 49.6% were male. Mean serum levels were; leptin: 4.3 ± 5.2 ng/ml, CRP: 0.19 ± 0.42 µg/ml, IL-6: 2.8 ± 5 pg/ml, and TNF-α: 5.3 ± 5.2 pg/ml. Obesity indices were associated with leptin and CRP in the third and fourth quartiles in single models. In combined models, associations were observed between BMI (OR = 6.36 [95% CI, 1.09; 34.12]); WC (OR = 4.87 [95% CI, 1.59; 14.94]); and %BF (OR = 19.23 [95% CI, 4.70; 78.66]) and leptin in the fourth quartile; also between %BF and CRP in the third quartile (OR = 3.49 [95% CI 1.31; 9.31]).

Conclusion: Total body fat was associated with low-grade inflammation in this tropical population rather than body fat distribution such as abdominal obesity. This may increase the risk of insulin resistance and other obesity-related metabolic and cardiovascular health endpoints.