Thursday, November 17, 2011
Pathological
History of Socioeconomic Disadvantage and Allostatic Load in Later Life
Tara Gruenewald et al.
Social Science & Medicine, forthcoming
Abstract:
There is a growing interest in understanding how the experience of socioeconomic status (SES) adversity across the life course may accumulate to negatively affect the functioning of biological regulatory systems important to functioning and health in later adulthood. The goal of the present analyses was to examine whether greater life course SES adversity experience would be associated with higher scores on a multi-system allostatic load (AL) index of physiological function in adulthood. Data for these analyses are from 1,008 participants (92.2% White) from the Biomarker Substudy of the Study of Midlife in the US (MIDUS). Multiple indicators of SES adversity in childhood (parent educational attainment, welfare status, financial situation) and two points in adulthood (educational attainment, household income, difficulty paying bills, availability of money to meet basic needs, current financial situation) were used to construct SES adversity measures for each life course phase. An AL score was constructed using information on 24 biomarkers from 7 different physiological systems (sympathetic and parasympathetic nervous systems, hypothalamic-pituitary-adrenal axis, cardiovascular, lipid metabolism, glucose metabolism, inflammatory immune activity). Analyses indicate higher AL as a function of greater SES adversity at each phase of, and cumulatively across, the life course. Associations were only moderately attenuated when accounting for a wide array of health status, behavioral and psychosocial factors. Findings suggest that SES adversity experience may cumulate across the life course to have a negative impact on multiple biological systems in adulthood. An important aim of future research is the replication of current findings in this predominantly White sample in more ethnically diverse populations.
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Junenette Peters et al.
American Journal of Epidemiology, forthcoming
Abstract:
Pessimism, a general tendency toward negative expectancies, is a risk factor for depression and also heart disease, stroke, and reduced cancer survival. There is evidence that individuals with higher lead exposure have poorer health. However, low socioeconomic status (SES) is linked with higher lead levels and greater pessimism, and it is unclear whether lead influences psychological functioning independently of other social factors. The authors considered interrelations among childhood and adult SES, lead levels, and psychological functioning in data collected on 412 Boston area men between 1991 and 2002 in a subgroup of the VA Normative Aging Study. Pessimism was measured by using the Life Orientation Test. Cumulative (tibia) lead was measured by x-ray fluorescence. Structural equation modeling was used to quantify the relations as mediated by childhood and adult SES, controlling for age, health behaviors, and health status. An interquartile range increase in lead quartile was associated with a 0.37 increase in pessimism score (P < 0.05). Low childhood and adult SES were related to higher tibia lead levels, and both were also independently associated with higher pessimism. Lead maintained an independent association with pessimism even after childhood and adult SES were considered. Results demonstrate an interrelated role of lead burden and SES over the life course in relation to psychological functioning in older age.
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Urban Annoyances and Mental Health in the City of Lahore, Pakistan
Nuzrat Yar Khan et al.
Journal of Urban Affairs, forthcoming
Abstract:
Lahore has undergone rapid urbanization in recent decades. Population growth has far exceeded carrying capacity of municipal infrastructure, causing stress. We conducted a survey to assess citizens' responses to urban annoyances and prevalence of depression, loss of self-esteem, and loss of resilience. An 84-item questionnaire was used to interview a sample of 370 respondents. Statistical analyses included correlations, ANOVA, factor analysis, and Multiple Regression Analysis. Results showed that respondents were disturbed by urban annoyances. Those disturbed were also depressed, had low self-esteem, low resilience, and an external locus of control. Depression was strongly affected by education, population density, and household congestion. We concluded that a degraded urban environment has caused psychological stress among citizens as reflected in the prevalence of depression, loss of self-esteem, and low resilience. There is an urgent need for strategic planning aimed at checking unbridled urban growth, improving civic services, and ensuring better mental health of citizens.
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National Trends in Mental Health Disability, 1997-2009
Ramin Mojtabai
American Journal of Public Health, November 2011, Pages 2156-2163
Objectives: I assessed recent trends in mental health disability in the US nonelderly adult population in the context of trends in physical disabilities and psychological distress.
Methods: Using data for 312364 adults aged 18 to 64 years from the US National Health Interview Survey, 1997 to 2009, I examined time trends in self-reported disability attributed to mental health conditions, disability attributed to other chronic problems, and significant psychological distress (measured by using the K6 instrument).
Results: The prevalence of self-reported mental health disability increased from 2.0% of the nonelderly adult population in the first 3 years (1997 to 1999) to 2.7% in the last 3 years (2007 to 2009), corresponding to an increase of almost 2 million disabled adults. Disability attributed to other chronic conditions decreased and significant psychological distress did not change appreciably. Change in self-reported mental health disability was more pronounced in adults who also reported disability attributed to other chronic conditions or significant psychological distress but who had no mental health contacts in the past year.
Conclusions: These findings highlight the need for improved access to mental health services in the community and for better integration of these services with primary care.
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Aimee James, Christine Daley & K.A. Greiner
Social Science & Medicine, December 2011, Pages 1669-1673
Abstract:
Many underserved groups in the United States experience disparities in cancer survival. Part of the disparity may be due to differences in treatment or treatment uptake. Previous studies uncovered patient beliefs that surgery could cause cancer to spread and have suggested that this belief may affect uptake of cancer treatment. We explored patients' explanations about surgical treatment of cancer and cancer spread, as well as the perceived impact on decision-making among primary care patients from an underserved area. Focus groups and interviews were conducted with patients (n = 42) at a primary care federally qualified health center in 2006 and 2007. Focus groups/interviews were semi-structured and were audio-taped and transcribed. An inductive text analysis with multiple coders was used to analyze the data and extract themes. We found that nearly all respondents had heard that surgery ("cutting") and exposing cancer to the air would hasten cancer spread and result in worse outcomes. Most participants expressed agreement with this belief. Many participants said this concern would influence their decision about whether to have surgery and/or reported that a family member had refused surgery for this reason. A smaller group of respondents disagreed with this belief and offered experiential evidence to the contrary or hypotheses about its origination. The idea that "cutting" and "air" during surgery can cause cancer to spread may be more prevalent among patients than suspected, based on this sample of predominantly African American patients. While we were unable to disentangle the ideas about "cutting" from those about "exposure to air", this set of beliefs, when held strongly, can negatively influence patients' or family members' decisions to seek surgical care and, if it is more prevalent in underserved groups, may contribute to cancer disparities.
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The lifespan consequences of early life stress
Anu-Katriina Pesonen & Katri Räikkönen
Physiology & Behavior, forthcoming
Abstract:
Early life stress (ELS), an experience of severe stress due for example to parental loss, abuse or neglect during the childhood years, may have profound long-term effects on the individual's physiology and psychology. Here we review the findings of the Helsinki Birth Cohort Study 1934-44 (n = 13,345), of whom approximately 14% were temporarily separated from both their parents due to child evacuations in World War II. The children were evacuated from Finland, unaccompanied by their parents, to other countries in Scandinavia (Sweden and Denmark) at the average age of 4.7 years (SD = 2.4 years) and for an average period of 1.7 years (SD = 1.0 years). Information on these separations for each member of the HBCS was derived from the Finnish National Archives. We found significant effects of ELS on psychiatric morbidity and mortality, intellectual ability, stress reactivity, reproductive history, and inter-generational social mobility.
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Long-Run Returns to Education: Does Schooling Lead to an Extended Old Age?
Hans van Kippersluis, Owen O'Donnell & Eddy van Doorslaer
Journal of Human Resources, Fall 2011, Pages 695-721
Abstract:
While there is no doubt that health is strongly correlated with education, whether schooling exerts a causal impact on health is not firmly established. We exploit a Dutch compulsory schooling law to estimate the causal effect of education on mortality. The reform provides a powerful instrument, significantly raising years of schooling, which, in turn, has a significant and robust negative effect on mortality. For men surviving to age 81, an extra year of schooling is estimated to reduce the probability of dying before the age of 89 by almost three percentage points relative to a baseline of 50 percent.
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Selective Out-Migration from Florida
Andy Sharma
Population Research and Policy Review, December 2011, Pages 817-838
Abstract:
I test if selective out-migration of unhealthy seniors explains why disability rates are so much lower for Florida, as compared to the national average. This particular area of research is timely given the significant demographic changes relating to aging. Moreover, this study contributes to the body of literature examining migration with respect to disability and widowhood. Using State Federal Information Processing Standard (FIPS) and Public Use Microdata Areas (PUMA), I create national maps showing disability rates for the following age-groups: 50-59, 60-69, and 70+. After creating maps in ARCGIS and conducting univariate and clustering analysis on mobility disability and personal care limitation, I employ multinomial logit (MNL) analysis to test if individuals with disability are more likely to out-migrate from Florida. The regression analyses lend support to the relaxed Litwak and Longino (The Gerontologist, 27(3): 266-272, 1987) second-move hypothesis, which claims individuals with progressively worse health are more likely to undertake another move to be closer to family and friends. I state "relaxed" because the data does not allow one to determine the reason for migration - only that migration occurred during the past year. This research informs policy-makers to recognize that elderly in better health may migrate to places such as Arizona and Florida due to amenity-seeking behavior, but unhealthy elderly are more likely to leave these states due to assistance-seeking behavior. This out-migration can place excess demand on health services for the incoming regions, which requires state and local government to ensure resources are in place. Also noteworthy, my results are less likely to be flawed by erroneous age and sex data in the public use microdata samples (IPUMS) since I stack the 2006 and 2007 American Community Survey (ACS). A recent working studies by Alexander et al. (Inaccurate age and sex data in the Census PUMS files: Evidence and implications. Munich: CESifo, 2010) shows inaccuracies in the IPUMS for the 1 and 5% 2000 Census, the 2003-2006 ACS, the 2005-2007 3-year ACS, and the 2004-2009 current population survey (CPS) files.
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Agricultural Policy, Migration, and Malaria in the 1930s United States
Alan Barreca, Price Fishback & Shawn Kantor
NBER Working Paper, October 2011
Abstract:
The Agricultural Adjustment Act (AAA) caused a population shift in the United States in the 1930s. Evaluating the effects of the AAA on the incidence of malaria can therefore offer important lessons regarding the broader consequences of demographic changes. Using a quasi-first difference model and a robust set of controls, we find a negative association between AAA expenditures and malaria death rates at the county level. Further, we find the AAA caused relatively low-income groups to migrate from counties with high-risk malaria ecologies. These results suggest that the AAA-induced migration played an important role in the reduction of malaria.
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Counting Calories: Democracy and Distribution in the Developing World
Lisa Blaydes & Mark Andreas Kayser
International Studies Quarterly, December 2011, Pages 887-908
Abstract:
How does regime type affect the poor? Are certain types of regimes better at translating economic growth into consumption for the world's least privileged citizens? We propose an alternative measure of transfers to the poor that is nearly universally available and innately captures distribution: average daily calorie consumption. In sharp contrast to the consumption of material goods or the accumulation of wealth for which humans have shown no upper bound on their ability to achieve, biological limits make it impossible for a small number of individuals to consume most of a nation's calories. Democracies and hybrid regimes - which combine elements of autocracy and democracy - are better at translating economic growth into total calorie consumption than autocracies and perform strikingly similarly in this regard; democracies outperform both hybrid regimes and autocracies, however, in converting growth into higher quality calories from animal sources.
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Dawn Alley et al.
American Journal of Public Health, December 2011, Pages 2293-2298
Objectives: We evaluated associations between mortgage delinquency and changes in health and health-relevant resources over 2 years, with data from the Health and Retirement Study, a longitudinal survey representative of US adults older than 50 years.
Methods: In 2008, participants reported whether they had fallen behind on mortgage payments since 2006 (n=2474). We used logistic regression to compare changes in health (incidence of elevated depressive symptoms, major declines in self-rated health) and access to health-relevant resources (food, prescription medications) between participants who fell behind on their mortgage payments and those who did not.
Results: Compared with nondelinquent participants, the mortgage-delinquent group had worse health status and less access to health-relevant resources at baseline. They were also significantly more likely to develop incident depressive symptoms (odds ratio [OR]=8.60; 95% confidence interval [CI]=3.38, 21.85), food insecurity (OR=7.53; 95% CI=3.01, 18.84), and cost-related medication nonadherence (OR=8.66; 95% CI=3.72, 20.16) during follow-up.
Conclusions: Mortgage delinquency was associated with significant elevations in the incidence of mental health impairments and health-relevant material disadvantage. Widespread mortgage default may have important public health implications.
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Basile Chaix et al.
Social Science & Medicine, November 2011, Pages 1543-1550
Abstract:
Although studies have shown that resting heart rate (RHR) is predictive of cardiovascular morbidity/mortality, few studies focused on the epidemiology and social aetiology of RHR. Using the RECORD Cohort Study (7158 participants, 2007-2008, Paris region, France), we investigated individual/neighbourhood socioeconomic variables associated with resting heart rate, and assessed which of a number of psychological factors (depression and stress), behaviour (sport-related energy expenditure, medication use, and alcohol, coffee, and tobacco consumption), life course anthropometric factors (body mass index, waist circumference, and leg length as a marker of childhood environmental exposures), and biologic factors (alkaline phosphatase and gamma-glutamyltransferase) contributed to the socioeconomic disadvantage-RHR relationship. Combining individual/neighbourhood socioeconomic factors in a socioeconomic score, RHR increased with socioeconomic disadvantage: +0.9 [95% credible interval (CrI): +0.2, +1.6], +1.8 (95% CrI: +1.0, +2.5), and +3.6 (95% CrI: +2.9, +4.4) bpm for the 3 categories reflecting increasing disadvantage, compared with the lowest disadvantage category. Twenty-one percent of the socioeconomic disadvantage-RHR relationship was explained by sport practise variables, 9% by waist circumference, 7% by gamma-glutamyltransferase, 5% by alkaline phosphatase, and 3% by leg length. Future research should further clarify the mechanisms through which socioeconomic disadvantage influences resting heart rate, as a pathway to social disparities in cardiovascular morbidity/mortality.
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Corruption Kills: Estimating the Global Impact of Corruption on Children Deaths
Matthieu Hanf et al.
PLoS ONE, November 2011, e26990
Background: Information on the global risk factors of children mortality is crucial to guide global efforts to improve survival. Corruption has been previously shown to significantly impact on child mortality. However no recent quantification of its current impact is available.
Methods: The impact of corruption was assessed through crude Pearson's correlation, univariate and multivariate linear models coupling national under-five mortality rates in 2008 to the national "perceived level of corruption" (CPI) and a large set of adjustment variables measured during the same period.
Findings: The final multivariable model (adjusted R2 = 0.89) included the following significant variables: percentage of people with improved sanitation (p.value<0.001), logarithm of total health expenditure (p.value = 0.006), Corruption Perception Index (p.value<0.001), presence of an arid climate on the national territory (p = 0.006), and the dependency ratio (p.value<0.001). A decrease in CPI of one point (i.e. a more important perceived corruption) was associated with an increase in the log of national under-five mortality rate of 0.0644. According to this result, it could be roughly hypothesized that more than 140000 annual children deaths could be indirectly attributed to corruption.
Interpretations: Global response to children mortality must involve a necessary increase in funds available to develop water and sanitation access and purchase new methods for prevention, management, and treatment of major diseases drawing the global pattern of children deaths. However without paying regard to the anti-corruption mechanisms needed to ensure their proper use, it will also provide further opportunity for corruption. Policies and interventions supported by governments and donors must integrate initiatives that recognise how they are inter-related.
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Contextual Predictors of Cumulative Biological Risk: Segregation and Allostatic Load
Anna Bellatorre et al.
Social Science Quarterly, December 2011, Pages 1338-1362
Objectives: Segregation is considered to be a fundamental cause of race/ethnic disparities in health. However, very few studies have tested whether levels of segregation are related to health outcomes using multilevel data and appropriate methodologies. In this study, we investigate the relationships between two distinct dimensions of segregation and allostatic load to determine whether the experiences of individuals in segregated neighborhoods are related to allostatic load as a possible predisease indicator.
Methods: To test our hypotheses, we utilized publicly available data from the National Health and Nutrition Examination Survey III, 1988-1994. We utilized random-intercept hierarchical generalized Poisson regression models to conduct our multivariate analyses.
Results: We find that inflammatory response is related to both the evenness and exposure domains of segregation. That is, both the unequal distribution of minority groups over areal units as well as the degree of potential contact between minority and majority group members are related to these predisease pathways.
Conclusions: In this study, we build on prior research by Massey (2004) to investigate the relationships between two distinct dimensions of segregation and allostatic load. Our results indicate that segregation is a significant predictor of allostatic load, net of individual-level characteristics.
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Perception of racial discrimination and psychopathology across three U.S. ethnic minority groups
Tina Chou, Anu Asnaani & Stefan Hofmann
Cultural Diversity and Ethnic Minority Psychology, forthcoming
Abstract:
To examine the association between the perception of racial discrimination and the lifetime prevalence rates of psychological disorders in the three most common ethnic minorities in the United States, we analyzed data from a sample consisting of 793 Asian Americans, 951 Hispanic Americans, and 2,795 African Americans who received the Composite International Diagnostic Interview through the Collaborative Psychiatric Epidemiology Studies. The perception of racial discrimination was associated with the endorsement of major depressive disorder, panic disorder with agoraphobia, agoraphobia without history of panic disorder, posttraumatic stress disorder, and substance use disorders in varying degrees among the three minority groups, independent of the socioeconomic status, level of education, age, and gender of participants. The results suggest that the perception of racial discrimination is associated with psychopathology in the three most common U.S. minority groups.
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Race/ethnic differences in adult mortality: The role of perceived stress and health behaviors
Patrick Krueger, Jarron Saint Onge & Virginia Chang
Social Science & Medicine, November 2011, Pages 1312-1322
Abstract:
We examine the role of perceived stress and health behaviors (i.e., cigarette smoking, alcohol consumption, physical inactivity, sleep duration) in shaping differential mortality among whites, blacks, and Hispanics. We use data from the 1990 National Health Interview Survey (N = 38,891), a nationally representative sample of United States adults, to model prospective mortality through 2006. Our first aim examines whether unhealthy behaviors and perceived stress mediate race/ethnic disparities in mortality. The black disadvantage in mortality, relative to whites, closes after adjusting for socioeconomic status (SES), but re-emerges after adjusting for the lower smoking levels among blacks. After adjusting for SES, Hispanics have slightly lower mortality than whites; that advantage increases after adjusting for the greater physical inactivity among Hispanics, but closes after adjusting for their lower smoking levels. Perceived stress, sleep duration, and alcohol consumption do not mediate race/ethnic disparities in mortality. Our second aim tests competing hypotheses about race/ethnic differences in the relationships among unhealthy behaviors, perceived stress, and mortality. The social vulnerability hypothesis predicts that unhealthy behaviors and high stress levels will be more harmful for race/ethnic minorities. In contrast, the Blaxter (1990) hypothesis predicts that unhealthy lifestyles will be less harmful for disadvantaged groups. Consistent with the social vulnerability perspective, smoking is more harmful for blacks than for whites. But consistent with the Blaxter hypothesis, compared to whites, current smoking has a weaker relationship with mortality for Hispanics, and low or high levels of alcohol consumption, high levels of physical inactivity, and short or long sleep hours have weaker relationships with mortality for blacks.
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Jung Min Park, Angela Fertig & Paul Allison
American Journal of Public Health, December 2011, Pages S255-S261
Objectives: We assessed the independent effect of homeless and doubled-up episodes on physical and mental health, cognitive development, and health care use among children.
Methods: We used data from 4 waves of the Fragile Families and Child Wellbeing Study, involving a sample of 2631 low-income children in 20 large US cities who have been followed since birth. Multivariate analyses involved logistic regression using the hybrid method to include both fixed and random effects.
Results: Of the sample, 9.8% experienced homelessness and an additional 23.6% had a doubled-up episode. Housing status had little significant adverse effect on child physical or mental health, cognitive development, or health care use.
Conclusions: Family and environmental stressors common to many children in poverty, rather than just homeless and doubled-up episodes, were associated with young children's poor health and cognitive development and high health care use. Practitioners need to identify and respond to parental and family needs for support services in addition to housing assistance to effectively improve the health and development of young children who experience residential instability, particularly those in homeless families.
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Dongwoo Yoo
Economics & Human Biology, forthcoming
Abstract:
Factors related to geography such as climate, natural resources or waterways often affect human activities. However, traditional approaches such as Ordinary Least Squares (OLS) have limitations in investigating such patterns. Unlike OLS regression, Geographically Weighted Regression (GWR) allows the coefficients of explanatory variables to differ by locality by giving relatively more weight to geographically close observations. GWR depicts spatial patterns. This paper examines the pattern of height and crude death rate in the United States prior to the Civil War by this method. The GWR results show that access to water transportation increased mortality and decreased stature in the food exporting areas of the Midwest, and the opposite pattern appeared in the food importing areas of the Northeast.
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School Quality and the Education-Health Relationship: Evidence from Blacks in Segregated Schools
David Frisvold & Ezra Golberstein
Journal of Health Economics, forthcoming
Abstract:
In this paper, we estimate the effect of school quality on the relationship between schooling and health outcomes using the substantial improvements in the quality of schools attended by black students in the segregated southern states during the mid-1900s as a source of identifying variation. Using data from the National Health Interview Survey, our results suggest that improvements in school quality, measured as the pupil-teacher ratio, average teachers' wage, and length of the school year, amplify the beneficial effects of education on several measures of health in later life, including self-rated health, smoking, obesity, and mortality.
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Lilian Calderón-Garcidueñas et al.
Brain and Cognition, December 2011, Pages 345-355
Abstract:
Exposure to severe air pollution produces neuroinflammation and structural brain alterations in children. We tested whether patterns of brain growth, cognitive deficits and white matter hyperintensities (WMH) are associated with exposures to severe air pollution. Baseline and 1 year follow-up measurements of global and regional brain MRI volumes, cognitive abilities (Wechsler Intelligence Scale for Children-Revised, WISC-R), and serum inflammatory mediators were collected in 20 Mexico City (MC) children (10 with white matter hyperintensities, WMH+, and 10 without, WMH-) and 10 matched controls (CTL) from a low polluted city. There were significant differences in white matter volumes between CTL and MC children - both WMH+ and WMH- - in right parietal and bilateral temporal areas. Both WMH- and WMH+ MC children showed progressive deficits, compared to CTL children, on the WISC-R Vocabulary and Digit Span subtests. The cognitive deficits in highly exposed children match the localization of the volumetric differences detected over the 1 year follow-up, since the deficits observed are consistent with impairment of parietal and temporal lobe functions. Regardless of the presence of prefrontal WMH, Mexico City children performed more poorly across a variety of cognitive tests, compared to CTL children, thus WMH+ is likely only partially identifying underlying white matter pathology. Together these findings reveal that exposure to air pollution may perturb the trajectory of cerebral development and result in cognitive deficits during childhood.
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Mismatched racial identities, colourism, and health in Toronto and Vancouver
Gerry Veenstra
Social Science & Medicine, October 2011, Pages 1152-1162
Abstract:
Using original telephone survey data collected from adult residents of Toronto (n=685) and Vancouver (n=814) in 2009, I investigate associations between mental and physical health and variously conceived racial identities. An ‘expressed racial identity' is a self-identification with a racial grouping that a person will readily express to others when asked to fit into official racial classifications presented by Census forms, survey researchers, insurance forms, and the like. Distinguishing between Asian, Black, South Asian, and White expressed racial identities, I find that survey respondents expressing Black identity are the most likely to report high blood pressure or hypertension, a risk that is slightly attenuated by socioeconomic status, and that respondents expressing Asian identity are the most likely to report poorer self-rated mental health and self-rated overall health, risks that are not explained by socioeconomic status. I also find that darker-skinned Black respondents are more likely than lighter-skinned Black respondents to report poor health outcomes, indicating that colourism, processes of discrimination which privilege lighter-skinned people of colour over their darker-skinned counterparts, exists and has implications for well-being in Canada as it does in the United States. Finally, ‘reflected racial identity' refers to the racial identity that a person believes that others tend to perceive him or her to be. I find that expressed and reflected racial identities differ from one another for large proportions of self-expressed Black and South Asian respondents and relatively few self-expressed White and Asian respondents. I also find that mismatched racial identities correspond with relatively high risks of various poor health outcomes, especially for respondents who consider themselves White but believe that others tend to think they are something else. I conclude by presenting a framework for conceptualizing multifaceted suites of racial identities and relating their various components and inconsistencies between them to health outcomes.
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Epigenetics and environmental exposures
Richard Stein
Journal of Epidemiology and Community Health, forthcoming
Abstract:
It is becoming increasingly apparent that genetic factors are inadequate to fully explain many processes that shape development and disease. For example, monozygotic twin pairs, despite sharing identical DNA sequences, are often discordant for many traits and diseases, indicating that the same genotype can give rise to distinct phenotypes. This points towards the involvement of additional factors that cannot be explained solely by the sequence of the genome. Epigenetic modifications, defined as heritable changes that do not alter the nucleotide sequence, emerge as key factors that regulate chromatin structure and gene expression and, together with genetic factors, provide the mechanistic basis to understand the biological effects of various classes of environmental exposures. Epigenetic mechanisms explain the ability of certain chemical compounds to initiate biological perturbations that can lead to malignancy, despite being weak mutagens or lacking mutagenic activity altogether - a view that challenges old beliefs and opens new avenues in public health. The field of epigenetics also explains the causal link between certain infectious diseases and cancer, a relationship that was first observed over a century ago and was initially discounted, then fell into oblivion and more recently re-emerged as an important concept in biology. A key feature that distinguishes epigenetic modifications from genetic changes is their reversible nature. This provides exciting prophylactic and therapeutic perspectives, some of which already materialised with the approval of the first drugs that modulate the epigenetic machinery, reinforcing the idea that our genes are not our destiny.
