TABLE 1.
List of studies that looked at exposure and its effect on aging in human studies.
| Exposure | Cohort information | Findings | References |
| PM2.5 | 166 non-smoking elderly | 5 μg/m3 increment in annual PM2.5 concentration was associated with a relative decrease of 16.8% (95% CI: –26.0%, –7.4%, p = 0.0005) in telomere length and a relative decrease of 25.7% (95% CI: –35.2%, –16.2%, p < 0.0001) in mtDNA content. | Pieters et al., 2016 |
| PM2.5 | Birth cohort study of 641 mother-new born pairs | Mothers with higher residential exposure; mothers gave birth to new-borns with significantly lower telomere length; a 5 μg/m3 increase in residential PM2.5 exposure during pregnancy, cord blood telomeres were 9% shorter and placental telomeres 13% shorter. | Martens et al., 2017 |
| PM2.5 (indoor) | First group (N = 874) and a second examination group (N = 1003) | Indoor PM2.5 exposure levels were positively associated with skin aging symptoms, i.e., score of pigment spots on forehead (12.5% more spots per increase of IQR, P − 0.0371), and wrinkle on upper lip (7.7% more wrinkle on upper lip per increase of IQR, P − 0.0218). | Ding et al., 2017 |
| PM2.5 component species (ammonium, elemental carbon, organic carbon, nitrate, and sulfate) | 552 participants from the Normative Aging (yr. 2000–2011) (n = 940 visits) | Interquartile range increases in both 1-year sulfate (95%CI: 0.28, 0.74, P < 0.0001) and ammonium (95%CI: 0.02, 0.70, P = 0.04) levels were associated with at least a 0.36-year increase in Horvath DNAm-age; sulfate and ammonium were most associated with Horvath DNAm-age and suggest that DNAm-age measures differ in their sensitivity to ambient particle exposures and potentially disease. | Nwanaji-Enwerem et al., 2017 |
| Air pollution (PM10, PM2.5, PM2.5 absorbance/black carbon (BC), and NOx) | KORA F4 cohort | BC and PM10 were broadly associated with biological aging in men; long-term exposure to air pollution is associated with biological aging measures, potentially in a sex-specific manner. | Ward-Caviness et al., 2016 |
| Indoor pollution | Pingding (in northern China): N = 405; in Taizhou (in southern China) N = 857 women between 30 and 90 years of age | cooking with solid fuels was significantly associated with a 5–8% more severe wrinkle appearance on face and an 74% increased risk of having fine wrinkles on back of hands in both studies combined, independent of age and other influences on skin aging. | Li et al., 2015 |
| BC | Male participants of the Normative Aging Study in the greater Boston, MA, United States | Association between BC and blood markers were not observed in main effects models or when stratified by obesity status; BC was positively associated with markers of inflammation in men with CHD (particularly vascular endothelial growth factor) and in men with diabetes (particularly interleukin-1β and tumor necrosis factor-α). | Fang et al., 2012 |
| Smoking | 966 individuals who participated in a case-control study to investigate environmental and genetic risk factors for skin cancer | Association among increasing age, sun exposure, and amount of telangiectasia was strong among men, but less apparent among women; smoking was also associated with elastosis among both sexes, and with telangiectasia predominantly among men. | Kennedy et al., 2003 |
| Smoking | Spanish population, 1,474 participants (18–60 years old) | Most participants had Fitzpatrick skin phototype II (44.1%) and skin aging in accordance with their current age (69.0%); age, smoking habit, use of sunscreen and use of cosmetics were all significant independent predictors of skin aging. | Buendía-Eisman et al., 2020 |
| Lead | 459 men, Normative Aging Study, Boston | Blood lead concentration was positively and significantly associated with concurrent concentration of serum creatinine (P = 0.005); a10-fold increase in blood lead level predicted an increase of 7 μmol/L (0.08 mg/dL) in serum creatinine concentration; demonstrated impaired renal function in middle-aged and older men. | Kim et al., 1996 |
| Lead | 744 men, Normative Aging Study of the Department of Veterans Affairs | Rate of creatinine clearance was significantly and negatively associated with increasing levels of blood lead. | Payton et al., 1994 |
| Lead | 777 male participants (August 1991 and October 1996) in the Department of Veterans Affairs Normative Aging Study | A positive association between patellar bone lead and uric acid levels (P = 0.02); 52 (6.7%) participants had developed gouty arthritis; neither bone nor blood lead levels predicted gout in this cohort. | Shadick et al., 2000 |
| Anaesthesia | 1819 subjects with median (25th and 75th percentiles) follow-up of 5.1 (2.7–7.6) year and 4 (3–6) cognitive assessments | In older adults, exposure to general anaesthesia and surgery was associated with a subtle decline in cognitive z-scores. | Schulte et al., 2018 |
| Solvents | 41 floor layers and 40 carpenters | Among the oldest subjects (>60 years), only floor layers showed decline in visual memory; most highly exposed floor layers deteriorated significantly more than their referents in visual memory and perceptual speed. | Nilson, 2002 |
Studies have mostly focused on PM2.5 (indoor and outdoor), smoking, lead (Pb), and other exposures.