Population differences in associations between C-reactive protein concentration and adiposity: comparison of young adults in the Philippines and the United States

Abstract

Background: Inflammation may be an important mediator of the association between nutrition and cardiovascular diseases, but most studies have been conducted in Western populations with high rates of overweight and obesity and low levels of infectious disease.

Objectives: This study sought to investigate the predictors of C-reactive protein (CRP) in young adults living in the Philippines and to examine patterns of association with adiposity compared with young adults in the United States.

Design: Maximum likelihood logistic regression models were used to predict elevated high-sensitivity CRP (>3 mg/L) in relation to anthropometric measures of adiposity, symptoms of infectious disease, and proxy measures of pathogen exposure in men and women from the Philippines (n = 1648; age: 20-22 y). Comparative data were drawn from a nationally representative sample in the United States (National Health and Nutrition Examination Survey; n = 616; age: 19-24 y).

Results: Median concentrations of CRP were substantially lower in the Philippines (0.2 mg/L) than in the United States (0.9 mg/L), and the likelihood of elevated CRP was lower in the Philippines than in the United States at the same level of waist circumference or skinfold thickness. In the Philippines, infectious symptoms and pathogen exposure predicted elevated CRP, independent of adiposity.

Conclusions: Adiposity and infectious exposures are associated with elevated CRP in the Philippines; other populations undergoing comparable lifestyle and dietary changes associated with increasing rates of overweight and obesity are likely experiencing similar double burdens of inflammatory stimuli. Low concentrations of CRP in this Philippine sample raise the question of whether CRP cutoffs based on European or European-American reference populations are appropriate for predicting disease risk in populations undergoing the nutrition transition.

FIGURE 1

Proportion of young adults with C-reactive protein >3 mg/L and >10 mg/L in the Philippines (n = 1648) and the United States (n = 616), by sex. NHANES, National Health and Nutrition Examination Survey.

FIGURE 2

Probability of C-reactive protein (CRP) concentrations >3 mg/L (95% CI) in relation to waist circumference (cm) in the Philippines and the United States (excluding individuals with CRP >10 mg/L). The population-specific distribution of waist circumference (5th percentile, median, 95th percentile) is presented at the top of the figure. Probabilities are based on predictions from a maximum likelihood regression model including variables for smoking and oral contraceptive use. For the Philippines, n = 705 and 889 for females and males, respectively; for the National Health and Nutrition Examination Survey (NHANES), n = 246 and 295 for females and males, respectively.

FIGURE 3

Probability of C-reactive protein (CRP) concentrations >3 mg/L (95% CI) in relation to skinfold thickness (triceps + subscapular) in the Philippines and the United States (excluding individuals with CRP >10 mg/L). The population-specific distribution of skinfold thickness (5th percentile, median, 95th percentile) is presented at the top of the figure. Probabilities are based on predictions from a maximum likelihood regression model including variables for smoking and oral contraceptive use. Probabilities are based on predictions from a maximum likelihood regression model including variables for smoking and oral contraceptive use. For the Philippines, n = 705 and 889 for females and males, respectively; for the National Health and Nutrition Examination Survey (NHANES), n = 246 and 295 for females and males, respectively.

FIGURE 4

Median C-reactive protein (CRP) concentrations (25th and 75th percentiles) in relation to waist circumference in the Philippines and the United States; individuals with CRP concentrations >10 mg/L were excluded. For the Philippines, n = 705 and 889 for females and males, respectively; for the National Health and Nutrition Examination Survey (NHANES), n = 246 and 295 for females and males, respectively.

FIGURE 5

Median C-reactive protein (CRP) concentration (25th and 75th percentiles) in relation to skinfold thickness (mm; triceps + subscapular) in the Philippines and the United States. For the Philippines, n = 705 and 889 for females and males, respectively; for the National Health and Nutrition Examination Survey (NHANES), n = 246 and 295 for females and males, respectively.