Variability of C-reactive protein in first-generation Ecuadorian immigrants living in the United States

Three common assumptions about inflammation, aging, and health that are probably wrong

Chronic inflammation contributes to the onset and progression of cardiovascular disease and other degenerative diseases of aging. But does it have to? This article considers the associations among inflammation, aging, and health through the lens of human population biology and suggests that chronic inflammation is not a normal nor inevitable component of aging. It is commonly assumed that conclusions drawn from research in affluent, industrialized countries can be applied globally; that aging processes leading to morbidity and mortality begin in middle age; and that inflammation is pathological. These foundational assumptions have shifted focus away from inflammation as a beneficial response to infection or injury and toward an understanding of inflammation as chronic, dysregulated, and dangerous. Findings from community-based studies around the world-many conducted in areas with relatively high burdens of infectious disease-challenge these assumptions by documenting substantial variation in levels of inflammation and patterns of association with disease. They also indicate that nutritional, microbial, and psychosocial environments in infancy and childhood play important roles in shaping inflammatory phenotypes and their contributions to diseases of aging. A comparative, developmental, and ecological approach has the potential to generate novel insights into the regulation of inflammation and how it relates to human health over the life course.

Early life, life course and gender influences on levels of C-reactive protein among migrant Bangladeshis in the UK

Background and objectives

Humans co-evolved with pathogens, especially helminths, that educate the immune system during development and lower inflammatory responses. The absence of such stimuli in industrialized countries is associated with higher baseline levels of C-reactive protein (CRP) among adults who appear at greater risk for inflammatory disorders. This cross-sectional study examined effects of early life development on salivary CRP levels in 452 British-Bangladeshis who spent varying periods growing up in Bangladesh or UK. We also analyzed how gender and central obesity modulate effects on CRP. We hypothesized that: (i) first-generation Bangladeshis with higher childhood exposure to pathogens would have chronically lower CRP levels than second-generation British-Bangladeshis; (ii) effects would be greater with early childhoods in Bangladesh; (iii) effects by gender would differ; and (iv) increasing obesity would mitigate early life effects.

Methodology

Saliva samples were assayed for CRP using ELISAs, and anthropometric data collected. Participants completed questionnaires about demographic, socioeconomic, lifestyle and health histories. Data were analyzed using multiple linear regression.

Results

First-generation migrants who spent early childhoods in mostly rural, unhygienic areas, and moved to UK after age 8, had lower salivary CRP compared to the second-generation. Effects differed by gender, while waist circumference predicted higher CRP levels. CRP increased with years in UK, alongside growing obesity.

Conclusions and implications

Our study supports the hypothesis that pathogen exposure in early life lowers inflammatory responses in adults. However, protective effects differed by gender and can be eroded by growing obesity across the life course which elevates risks for other inflammatory disorders.

Lay Summary: Migrants to the UK who spent early childhoods in less hygienic environments in Bangladesh that help to educate their immune systems had lower levels of the inflammatory marker, C-reactive protein (CRP) compared to migrants who grew up in UK. Both gender and increasing obesity were associated with increased levels of CRP.