Anemia, a highly prevalent disorder in elderly populations, is associated with numerous adverse health outcomes, including increased mortality, impaired functional status and cognitive disorders. Approximately two-thirds of anemia in American elderly is caused by chronic inflammation or is unexplained. A potential contributing factor may include air pollution exposures, which have been shown to increase systemic inflammation and affect erythropoiesis. Few studies, however, have investigated the associations of air pollution on hemoglobin levels and anemia. We used linear regression models and modified Poisson regression with robust error variance to examine the associations of particulate matter (PM2.5) and nitrogen dioxide (NO2) on hemoglobin concentrations and prevalence of anemia, respectively, among 4121 older Americans enrolled in the National Social Life, Health, and Aging Project. We estimated participant-specific exposures to PM2.5 using spatio-temporal models, and to NO2 using nearest measurements from Environmental Protection Agency's Air Quality System. Hemoglobin levels were measured for participants in each of two data collection waves from dried blood spots. Anemia was defined using World Health Organization hemoglobin-based criteria of <13 and <12g/dL for men and women, respectively. Models were adjusted for age, sex, smoking status, race, income, education, neighborhood socioeconomic status, region, urbanicity and medication use. Mediation by C-reactive protein (CRP), a marker of systemic inflammation, was also investigated. An inter-quartile range (IQR, 3.9μg/m3) increase in the one-year moving average PM2.5 was positively associated with anemia prevalence (prevalence ratio, or PR 1.33, 95% CI: 1.23, 1.45) and decreases in average hemoglobin of 0.81g/dL (p<0.001). Similarly, an IQR (9.6ppb) increase in NO2 was associated with anemia prevalence (PR 1.43, 95% CI: 1.25, 1.63) and a decrease in average hemoglobin of 0.81g/dL (p<0.001). Strong dose-response relationships were identified for both pollutants. Mediation of the effect of PM2.5 by CRP was also identified (p=0.007). Air pollution exposures were significantly associated with increased prevalence of anemia and decreased hemoglobin levels in a cohort of older Americans. If causal, these associations could indicate that chronic air pollution exposure is an important risk factor for anemia in older adults.

Air pollution exposures have been shown to adversely impact health through a number of biological pathways associated with glucose metabolism. However, few studies have evaluated the associations between air pollution and glycosylated hemoglobin (HbA1c) levels. Further, no studies have evaluated these associations in US populations or investigated whether associations differ in diabetic as compared to non-diabetic populations. To address this knowledge gap, we investigated the associations between airborne fine particulate matter (PM2.5) and nitrogen dioxide (NO2) and HbA1c levels in both diabetic and non-diabetic older Americans. We also examined the impact of PM2.5 and NO2 on prevalent diabetes mellitus (DM) in this cohort. We used multilevel logistic and linear regression models to evaluate the association between long-term average air pollutant levels and prevalence of DM and HbA1c levels, respectively, among 4121 older (57+ years) Americans enrolled in the National Social Life, Health, and Aging Project between 2005 and 2011. All models adjusted for age, sex, body mass index, smoking status, race, household income, education level, neighborhood socioeconomic status, geographic region, urbanicity and diabetic medication use. We estimated participant-specific exposures to PM2.5 on a six-kilometer grid covering the conterminous U.S. using spatio-temporal models, and to NO2 using nearest measurements from the Environmental Protection Agency's Air Quality System. HbA1c levels were measured for participants in each of two data collection waves from dried blood spots and log-transformed prior to analysis. Participants were considered diabetic if they had HbA1c values≥6.5% or reported taking diabetic medication. The prevalence of diabetes at study entry was 22.2% (n=916) and the mean HbA1c was 6.0±1.1%. Mean one-year moving average PM2.5 and NO2 exposures were 10.4±3.0μg/m3 and 13.1±7.0 ppb, respectively. An inter-quartile range (IQR, 3.9μg/m3) increase in one-year moving average PM2.5 was positively associated with increased diabetes prevalence (prevalence odds ratio, POR 1.35, 95% CI: 1.19, 1.53). Similarly, an IQR (8.6 ppb) increase in NO2 was also significantly associated with diabetes prevalence (POR 1.27, 95% CI: 1.10, 1.48). PM2.5 (1.8%±0.6%, p<0.01) and NO2 (2.0%±0.7%, p<0.01) exposures were associated with higher HbA1c levels in diabetic participants, while only NO2 was significantly associated with HbA1c in non-diabetic participants (0.8%±0.2%, p<0.01). Significant dose response relationships were identified for both pollutants in diabetic participants and for NO2 in non-diabetic participants. In a cohort of older men and women in the United States, PM2.5 and NO2 exposures were significantly associated with prevalence of DM and increased HbA1c levels among both non-diabetic and diabetic participants. These associations suggest that air pollution could be a key risk factor for abnormal glucose metabolism and diabetes in the elderly.

Background: Health effects of air pollution on anaemia have been scarcely studied worldwide. We aimed to explore the associations of long-term exposure to ambient air pollutants with anaemia prevalence and haemoglobin levels in Chinese older adults. Methods: We used two-level linear regression models and modified Poisson regression with robust error variance to examine the associations of particulate matter (PM) and nitrogen dioxide (NO₂) on haemoglobin concentrations and the prevalence of anaemia, respectively, among 10,611 older Chinese adults enrolled in World Health Organization (WHO) Study on global AGEing and adult health (SAGE) China. The average community exposure to ambient air pollutants (PM with an aerodynamic diameter of 10 μm or less (PM₁₀), 2.5 μm or less (PM_2.5), 1 μm or less (PM₁) and nitrogen dioxide (NO₂)) for each participant was estimated using a satellite-based spatial statistical model. Haemoglobin levels were measured for participants from dried blood spots. The models were controlled for confounders. Results: All the studied pollutants were significantly associated with increased anaemia prevalence in single pollutant model (e.g., the prevalence ratios associated with an increase in inter quartile range in three years moving average PM₁₀ (1.05; 95% CI: 1.02–1.09), PM_2.5 (1.11; 95% CI: 1.06–1.16), PM₁ (1.13; 95% CI: 1.06–1.20) and NO₂ (1.42; 95% CI: 1.34–1.49), respectively. These air pollutants were also associated with lower concentrations of haemoglobin: PM₁₀ (−0.53; 95% CI: −0.67, −0.38); PM_2.5 (−0.52; 95% CI: −0.71, −0.33); PM₁ (−0.55; 95% CI: −0.69, −0.41); NO₂ (−1.71; 95% CI: −1.85, −1.57) respectively. Conclusions: Air pollution exposure was significantly associated with increased prevalence of anaemia and decreased haemoglobin levels in a cohort of older Chinese adults.

There is an established association between air pollution and cardiovascular disease (CVD), which is likely to be mediated by systemic inflammation. The present study evaluated links between long-term exposure to ambient air pollution and high-sensitivity C reactive protein (hs-CRP) in an older Chinese adult cohort (n = 7915) enrolled in the World Health Organization (WHO) study on global aging and adult health (SAGE) China Wave 1 in 2008–2010. Multilevel linear and logistic regression models were used to assess the associations of particulate matter (PM) and nitrogen dioxide (NO₂) on log-transformed hs-CRP levels and odds ratios of CVD risk derived from CRP levels adjusted for confounders. A satellite-based spatial statistical model was applied to estimate the average community exposure to outdoor air pollutants (PM with an aerodynamic diameter of 10 μm or less (PM₁₀), 2.5 μm or less (PM_2.5), and 1 μm or less (PM₁) and NO₂) for each participant of the study. hs-CRP levels were drawn from dried blood spots of each participant. Each 10 μg/m³ increment in PM₁₀, PM_2.5, PM₁, and NO₂ was associated with 12.8% (95% confidence interval; (CI): 9.1, 16.6), 15.7% (95% CI: 10.9, 20.8), 10.2% (95% CI: 7.3, 13.2), and 11.8% (95% CI: 7.9, 15.8) higher serum levels of hs-CRP, respectively. Our findings suggest that air pollution may be an important factor in increasing systemic inflammation in older Chinese adults.