Early-life Socioeconomic Status Research Articles

Early-life socioeconomic status and malocclusion in adolescents and young adults in Uruguay.

This study aims to estimate orthodontic treatment need among 15-24 year-old individuals in Montevideo, Uruguay, and the association of occlusal traits with demographic, clinical and socioeconomic factors, considering a life course approach. A cross-sectional study using data from the First National Oral Health Survey in Uruguay was conducted. A two-stage cluster procedure was used to select a sample of 278 individuals in Montevideo. Household interviews and oral examinations were performed by six dentists. Dental Aesthetic (DAI) and Decayed Missing and Filled Teeth Indices (DMFT) were used to assess orthodontic treatment need and dental caries, respectively. Early life and current socioeconomic factors were obtained from the interview. Ordinal logistic regression was used to model the DAI index. Prevalence of definite malocclusion was 20.6%, followed by severe (8.2%) and very severe (7.6%). In the adjusted analysis, individuals with untreated dental caries (OR = 1.11; 95%CI: 1.03-1.20) and those who reported a lower socioeconomic level at 6 years of age (OR = 5.52; 95%CI: 1.06-28.62) had a higher chance of being a worse case of malocclusion. Current socioeconomic position was not associated with orthodontic treatment need. Individuals aged 22-24 years (OR = 1.59; 95%CI: 1.05-2.41) had a lower chance than those aged 14-17. This study shows that orthodontic treatment need is relatively high in Uruguayan adolescents and young adults. There is a potential relationship between early life socioeconomic status and the occurrence of malocclusion in adolescents and young adults under a life course approach.

Early life socioeconomic status associates with interleukin-6 responses to acute laboratory stress in adulthood

It is proposed that environmental exposures in early life influence immune programming. Specifically, socioeconomic disadvantage is thought to program an immune phenotype that is prone to inflammation and associated with increased risk for inflammatory disease later in life. Existing literature shows an inverse association of early childhood socioeconomic status (SES) with adult levels of systemic inflammation. Here, we extend that literature to examine whether early childhood SES also relates to the magnitude of inflammatory response to acute psychological stress in adulthood. Healthy volunteers (N = 110; 40–58 years; 59% female; 90% white) performed a laboratory stress protocol, with blood samples drawn at the end of a 30-min baseline, a 5-min speech task, and a 30-min recovery to assess interleukin (IL)-6 stress responses. An early childhood SES index was derived from reports of parental home and vehicle ownership, and number of bedrooms per child in the home across ages 1–2, 3–4, and 5–6. Regressions adjusted for current age, sex, race, and BMI showed that lower SES at age 1–2 was associated with larger IL-6 stress responses in adulthood (ΔR2 = 0.05, β = −0.24, p = .03). This association was independent of adult SES and task-evoked affective responses. No association was found between SES at ages 3–4 or 5–6 and IL-6 responses. These results provide initial evidence for a link between disadvantage in the first 2 years of life and heightened inflammatory response to stress in adulthood; this link may contribute to the increased disease risk that accompanies being raised in disadvantaged socioeconomic circumstances.

Gender differences in the pathways from childhood disadvantage to metabolic syndrome in adulthood: An examination of health lifestyles

We investigate whether socioeconomic status (SES) in childhood shapes adult health lifestyles in domains of physical activity (leisure, work, chores) and diet (servings of healthy [i.e., nutrient-dense] vs. unhealthy [energy-dense] foods). Physical activity and food choices vary by gender and are key factors in the development of metabolic syndrome (MetS). Thus, we examined gender differences in the intervening role of these behaviors in linking early-life SES and MetS in adulthood. We used survey data (n = 1054) from two waves of the Midlife in the U.S. Study (MIDUS 1 and 2) and biomarker data collected at MIDUS 2. Results show that individuals who were disadvantaged in early life are more likely to participate in physical activity related to work or chores, but less likely to participate in leisure-time physical activity, the domain most consistently linked with health benefits. Women from low SES families were exceedingly less likely to complete recommended amounts of physical activity through leisure. Men from low SES consumed more servings of unhealthy foods and fewer servings of healthy foods. The observed associations between childhood SES and health lifestyles in adulthood persist even after controlling for adult SES. For men, lack of leisure-time physical activity and unhealthy food consumption largely explained the association between early-life disadvantage and MetS. For women, leisure-time physical activity partially accounted for the association, with the direct effect of childhood SES remaining significant. Evidence that material deprivation in early life compromises metabolic health in adulthood calls for policy attention to improve economic conditions for disadvantaged families with young children where behavioral pathways (including gender differences therein) may be shaped. The findings also underscore the need to develop gender-specific interventions in adulthood.

The Impact of Multiple Dimensions of Socioeconomic Status on Physical Functioning Across the Life Course.

Objective: We used the Physical Performance Across the LifeSpan Study to investigate the relationships of multiple indicators of socioeconomic status (SES), both in early life and late life, with physical function. Method: We examined associations between multiple early and late life SES indicators with physical function measured by aerobic endurance, gait speed, and lower body strength. Results: Higher participant education and household income were associated with increased physical function. In our age-stratified analysis, we observed widening SES disparities with increasing age among those in the two younger strata with lower SES associated with worse physical function. Finally, we observed an association between socioeconomic trend and gait speed, aerobic endurance, and lower body strength. There was also an association between lower aerobic endurance and being in a downward socioeconomic trend. Discussion: These findings highlight the significance of considering multiple dimensions of the social environment as important correlates of physical functioning across the life course.

Threat vigilance and socioeconomic disparities in metabolic health.

A quarter of the global population meets diagnostic criteria for metabolic syndrome (MetS). MetS prevalence stratifies by socioeconomic status (SES), such that low SES is associated with higher MetS risk starting in childhood. Despite this trend, some low-SES children maintain good metabolic health across the life span, but the factors responsible for their resilience are not well understood. This study examined the role of threat vigilance as either a moderator or a mediator of the effects of low early life SES on adult metabolic risk. Three hundred twenty-five Canadians aged 15-55 participated (M = 36.4 years, SD = 10.7; 55.4% female). We coded parental occupational status between the ages of 0 and 5 to index early life SES. We used the International Diabetes Federation case definition for MetS based on waist circumference, blood pressure, triglyceride levels, HDL cholesterol, and glycosylated hemoglobin measures. Threat vigilance was assessed using the Weapons Identification Procedure, a visual discrimination paradigm that captures implicit perceptions of threat. Analyses supported the moderator hypothesis: low early life SES was associated with MetS diagnosis exclusively among those with high levels of threat vigilance. This suggests that low early life SES environments that heighten vigilance to threat might be particularly detrimental for metabolic health. Conversely, low threat vigilance may buffer against the metabolic risks associated with socioeconomic disadvantage.

Childhood socioeconomic conditions and teeth in older adulthood: Evidence from SHARE wave 5.

Dental diseases are the most common chronic diseases worldwide. Healthy teeth are vital for quality of life, particularly diet and nutrition. However, little information exists to inform health policymakers about potentially long-lasting influences of early-life conditions. The purpose of this study was to investigate the relation between early-life socioeconomic conditions and number of natural teeth at age 50 and above. Analyses were conducted on cross-sectional data from the Survey of Health, Ageing and Retirement in Europe (SHARE wave 5), which includes information on 41 560 respondents aged 50 years or older from 14 European countries and Israel. Using SHARE life history information, a series of regression models (OLS, Tobit) were estimated to analyse the relationship between socioeconomic conditions in earlier life and the number of teeth at age 50+. Childhood socioeconomic background was associated with the number of natural teeth at age 50 and above, even after controlling for current determinants of oral health. Respondents who had had more than 25 books in their childhood household had a mean 1.4 (95% CI: 1.2-1.5) more teeth than respondents with fewer books. Respondents who reported poor financial conditions during childhood had a mean 0.6 (95% CI: 0.3-0.9) fewer teeth than respondents who reported better financial conditions in childhood. These findings substantiate the association between socioeconomic conditions in the early years of life and tooth retention to older adulthood and highlight the long-lasting relation between childhood living conditions and oral health through the lifecourse.

Adolescent socioeconomic status and depressive symptoms in later life: Evidence from structural equation models

BackgroundThe complex association between socioeconomic status (SES) and depressive symptoms is not entirely understood and the existing literature does not address the relationship between early-life SES and later-life depression from a life-course perspective, incorporating mediating events. MethodsUsing data from the Wisconsin Longitudinal Study, we employed structural equation modeling to examine how SES measured at age 18 affects depressive symptoms at age 54 directly and through mediating variables college graduation, marriage, and household income level at age 36. ResultsThe total effect of adolescent SES on later-life depressive symptoms is largely mediated through college graduation. Our final model was driven by the effects of women. The variables contributing most to depressive symptoms in women were the direct effect of being raised in a home with a low SES and the indirect effect of low adolescent SES mediated through non-completion of college. LimitationsCohort was exclusively comprised of white, high school graduates born in 1939 (± 2 years). In our analysis we assume that missing values are missing at random (MAR); however, attrition both from death (excluded from our population) and from non-response could be associated with depression, i.e. missing not at random (MNAR). ConclusionsThis study demonstrates the impact of completion of college, particularly among women, and supports the social mobility hypothesis to explain the relationship between adolescent socioeconomic circumstances and late-life health.

Intelligence and all-cause mortality in the 6-Day Sample of the Scottish Mental Survey 1947 and their siblings: testing the contribution of family background.

BackgroundHigher early-life intelligence is associated with a reduced risk of mortality in adulthood, though this association is apparently hardly attenuated when accounting for early-life socio-economic status (SES). However, the use of proxy measures of SES means that residual confounding may underestimate this attenuation. In the present study, the potential confounding effect of early-life SES was instead accounted for by examining the intelligence–mortality association within families.MethodsThe association between early-life intelligence and mortality in adulthood was assessed in 727 members of the 6-Day Sample of the Scottish Mental Survey 1947 and, for the first time, 1580 of their younger siblings. These individuals were born between 1936 and 1958, and were followed up into later life, with deaths recorded up to 2015. Cox regression was used to estimate the relative risk of mortality associated with higher IQ scores after adjusting for shared family factors.ResultsA standard-deviation advantage in IQ score was associated with a significantly reduced mortality risk [hazard ratio = 0.76, p < 0.001, 95% confidence interval (CI) (0.68–0.84)]. This reduction in hazard was only slightly attenuated by adjusting for sex and shared family factors [hazard ratio = 0.79, p = 0.002, 95% CI (0.68–0.92)].ConclusionsAlthough somewhat conservative, adjusting for all variance shared by a family avoids any potential residual confounding of the intelligence–mortality association arising from the use of proxy measures of early-life SES. The present study demonstrates that the longevity associated with higher early-life intelligence cannot be explained by early-life SES or within-family factors.

Early-Life Socioeconomic Conditions, Height, and Functional Health Status in Later Life: Evidence From South Korea.

The article contributes to the literature on health inequalities by examining the associations between early-life socioeconomic status (SES), height, and functional limitations in later life among Korean men and women. The findings were based on 1562 men and 1801 women aged 50 to 79 years who participated in the 2005 Korean Labor and Income Panel Study (KLIPS). Among men, 17.8% reported having functional limitations, compared to 31.8% among women. The ordered logistic regression analyses showed that for Korean men, the relative contribution of early-life SES to functional health was less important than that of adult SES. For Korean women, childhood SES was a significant predictor of functional limitations after controlling for attained SES. Short stature was associated with poorer functional health only among men and the relationship was explained by adult characteristics. The results imply that long-term effect of childhood deprivation on health may be stronger among women in Korean society.

Early-Life Socioeconomic Disadvantage and Metabolic Health Disparities

A quarter of the world's population have metabolic syndrome (MetS). MetS prevalence is stratified by socioeconomic status (SES), such that low SES is associated with higher MetS risk. The present study examined the relative roles of early-life SES and current SES in explaining MetS risk. Participants (N = 354; ages = 15-55 years, M [SD] = 36.5 [10.7] years; 55% female; 72.9% white, 16.9% Asian, 10.2% others) were evaluated for SES and MetS. All were in good health, defined as free of chronic medical illness and acute infectious disease. Using occupational status as a proxy for SES, we recruited roughly equal numbers of participants with low-low, low-high, high-low, and high-high combinations of early-life and current SES. We used the International Diabetes Federation definition for MetS using race- and sex-specific cutoffs for waist circumference, triglyceride levels, high-density lipoprotein cholesterol, blood pressure, and glycosylated hemoglobin levels. Analyses revealed a main effect of low early-life SES on increased MetS risk according to the three separate definitions. They included the traditional MetS diagnosis (odds ratio [OR] = 1.53, confidence interval [CI] = 1.01-2.33, p = .044), the number of MetS components for which diagnostic thresholds were met (OR = 1.61, CI = 1.10-2.38, p = .015), and a continuous indicator of metabolic risk based on factor analysis (F(1,350) = 6.71, p = .010, partial η = .019). There was also a significant interaction of early-life SES and current SES in predicting MetS diagnosis (OR = 1.54, CI = 1.02-2.34). The main effects of current SES were nonsignificant in all analyses. These findings suggest that MetS health disparities originate in childhood, which may be an opportune period for interventions.

Contribution of Socioeconomic Status at 3 Life-Course Periods to Late-Life Memory Function and Decline: Early and Late Predictors of Dementia Risk.

Both early life and adult socioeconomic status (SES) predict late-life level of memory; however, evidence is mixed on the relationship between SES and rate of memory decline. Further, the relative importance of different life-course periods for rate of late-life memory decline has not been evaluated. We examined associations between life-course SES and late-life memory function and decline. Health and Retirement Study participants (n = 10,781) were interviewed biennially from 1998-2012 (United States). SES measurements for childhood (composite score including parents' educational attainment), early adulthood (high-school or college completion), and older adulthood (income, mean age 66 years) were all dichotomized. Word-list memory was modeled via inverse-probability weighted longitudinal models accounting for differential attrition, survival, and time-varying confounding, with nonrespondents retained via proxy assessments. Compared to low SES at all 3 points (referent), stable, high SES predicted the best memory function and slowest decline. High-school completion had the largest estimated effect on memory (β = 0.19; 95% confidence interval: 0.15, 0.22), but high late-life income had the largest estimated benefit for slowing declines (for 10-year memory change, β = 0.35; 95% confidence interval: 0.24, 0.46). Both early and late-life interventions are potentially relevant for reducing dementia risk by improving memory function or slowing decline.

924. Socioeconomic Status in Early Childhood Predicts White Matter Integrity in Young Adulthood

Socioeconomic disadvantage confers higher risk for medical illness, psychiatric distress, and poor cognitive functioning (Gianaros, 2013). Changes in brain structure may be one mechanism linking low socioeconomic status (SES) to poor health outcomes (Ursache & Noble, 2016). Concurrent associations between SES and white matter microstructure have been reported in childhood (Ursache & Noble, 2016), late adolescence (Noble et al., 2013), and adulthood (Gianaros et al., 2013) in the cingulum, a pathway implicated in executive functioning and self-regulation. Longitudinal investigations are necessary to determine whether SES in early life can impact white matter microstructure later in development.

The association of early life socioeconomic conditions with prediabetes and type 2 diabetes: results from the Maastricht study

BackgroundUsing cross-sectional data from The Maastricht Study, we examined the association of socioeconomic conditions in early life with prediabetes and T2DM in adulthood. We also examined potential mediating pathways via both adulthood socioeconomic conditions and adult BMI and health behaviours.MethodsOf the 3263 participants (aged 40–75 years), 493 had prediabetes and 906 were diagnosed with T2DM. By using logistic regression analyses, the associations and possible mediating pathways were examined.ResultsParticipants with low early life socioeconomic conditions had a 1.56 times higher odds of prediabetes (95% confidence interval (CI) = 1.21-2.02) and a 1.61 times higher odds of T2DM (95% CI = 1.31-1.99). The relation between low early life socioeconomic conditions and prediabetes was independent of current socioeconomic conditions (OR = 1.38, 95% CI = 1.05-1.80), whereas the relation with T2DM was not independent of current socioeconomic conditions (OR = 1.10, 95% CI = 0.87-1.37). BMI party mediated the association between early life socioeconomic conditions and prediabetes.ConclusionsSocioeconomic inequalities starting in early life were associated with diabetes-related outcomes in adulthood and suggest the usefulness of early life interventions aimed at tackling these inequalities.

Early-Life Socioeconomic Status and Adult Physiological Functioning: A Life Course Examination of Biosocial Mechanisms

ABSTRACTA growing literature has demonstrated a link between early-life socioeconomic conditions and adult health at a singular point in life. No research exists, however, that specifies the life course patterns of socioeconomic status (SES) in relation to the underlying biological processes that determine health. Using an innovative life course research design consisting of four nationally representative longitudinal datasets that collectively cover the human life span from early adolescence to old age (Add Health, MIDUS, NSHAP, and HRS), we address this scientific gap and assess how SES pathways from childhood into adulthood are associated with biophysiological outcomes in different adult life stages. For each dataset, we constructed standardized composite measures of early-life SES and adult SES and harmonized biophysiological measurements of immune and metabolic functioning. We found that the relative importance of early-life SES and adult SES varied across young, mid, and late adulthood, such that early-life SES sets a life course trajectory of socioeconomic well-being and operates through adult SES to influence health as adults age. We also documented evidence of the detrimental health effects of downward mobility and persistent socioeconomic disadvantage. These findings are the first to specify the life course patterns of SES that matter for underlying biophysiological functioning in different stages of adulthood. The study thus contributes new knowledge critical for improving population health by identifying the particular points in the life course at which interventions might be most effective in preventing disease and premature mortality.

Early life socioeconomic environment and mammographic breast density

BackgroundEarly life social environment may influence breast cancer through shaping risk factors operating in early life, adolescence and adulthood, or may be associated with breast cancer risk independent of known risk factors. We investigated the associations between early life socioeconomic status (SES) and mammographic density, a strong risk factor for breast cancer, and the extent to which these associations were independent of risk factors across the lifecourse.MethodsWe used data from an adult follow-up study of two U.S. birth cohorts of women (average age = 43 years) with prospectively collected data starting during the pregnancy of the mother and continuing through early childhood of the offspring. We collected data on factors in later life periods through computer-assisted interviews with the offspring as adults, and obtained routine clinical mammograms for measurement of percent density and dense and nondense breast areas using a computer assisted method. We used generalized estimating equation models for multivariable analysis to account for correlated data for sibling sets within the study sample (n = 700 composed of 441 individuals and 127 sibling sets).ResultsHighest vs. lowest family income level around the time of birth was associated with smaller dense breast area after adjustment for early life factors (e.g., birthweight, maternal smoking during pregnancy) and risk factors in later life periods, including adult body mass index (BMI) and adult SES (β = −8.2 cm2, 95% confidence interval [CI]: −13.3, −3.2). Highest vs. lowest parental educational attainment was associated with higher percent density in models that adjusted for age at mammogram and adult BMI (e.g., β = 4.8, 95% CI = 0.6, 9.1 for maternal education of college or higher degree vs. less than high school), but the association was attenuated and no longer statistically significant after further adjustment for early life factors. There were no associations between early life SES indicators and non-dense area after adjustment for adult BMI. Neither adult education nor adult income was statistically significantly associated with any measure of mammographic density after adjusting for age and adult BMI.ConclusionsWe did not observe consistent associations between different measures of early life SES and mammographic density in adulthood.

An Uncertainty Management Perspective on Long-Run Impacts of Adversity: The Influence of Childhood Socioeconomic Status on Risk, Time, and Social Preferences

While there has been a recent increase in focus on the role of early life socioeconomic status (SES) on preferences and decision-making, there is still debate surrounding the proper theoretical framework for understanding such effects. Some have argued that early life SES can fundamentally shift time preferences per se, such that those from low SES backgrounds favor current rewards over future rewards. Others have argued that, while early life SES has lasting effects on behavior, such effects are only observable in the presence of salient cues to mortality. Here, we propose an alternative framework that centers on environmental uncertainty. In this uncertainty management framework, early life deprivation promotes the development of strategies that minimize the downside costs of uncertainty across domains. We argue that this focus on managing uncertainty results in greater risk-aversion, present- orientation, and prosociality. Furthermore, these effects need not be dependent on salient cues to mortality. Across four large samples of participants (total N=4,714), we find that childhood deprivation uniquely predicts greater risk-aversion (both incentivized and hypothetical) and greater prosociality in economic games. Childhood deprivation also predicts greater present-orientation, but not above-and beyond current SES. We further find that mortality cues are not necessary to elicit these differences. Our results support an uncertainty management perspective on the effects of childhood SES on risk, time, and social preferences.

Baby Boomers and Birth Certificates: Early-Life Socioeconomic Status and Cancer Risk in Adulthood.

Early-life socioeconomic status (SES) may play a role in cancer risk in adulthood. However, measuring SES retrospectively presents challenges. Parental occupation on the birth certificate is a novel method of ascertaining early-life SES that has not been applied in cancer epidemiology. For a Baby-Boom cohort born from 1945-1959 in two Utah counties, individual-level Nam-Powers SES (Np-SES) was derived from parental industry/occupation reported on birth certificates. Neighborhood SES was estimated from average household income of census tract at birth. Cancer incidence was determined by linkage to Utah Cancer Registry records through the Utah Population Database. Hazard ratios (HR) for cancer risk by SES quartile were estimated using Cox proportional hazards regression. Females with low Np-SES at birth had lower risk of breast cancer compared with those in the highest Np-SES group [HRQ1/Q4 = 0.83; 95% confidence interval (CI), 0.72-0.97; HRQ2/Q4 = 0.81; 95% CI, 0.69-0.96]. Np-SES was inversely associated with melanoma (HRQ1/Q4 = 0.81; 95% CI, 0.67-0.98) and prostate cancer (HRQ1/Q4 = 0.70; 95% CI, 0.56-0.88). Women born into lower SES neighborhoods had significantly increased risk for invasive cervical cancer (HRQ1/Q4 = 1.44; 95% CI, 1.12-1.85; HRQ2/Q4 = 1.33; 95% CI, 1.04-1.72). Neighborhood SES had similar effects for melanoma and prostate cancers, but was not associated with female breast cancer. We found no association with SES for pancreas, lung, and colon and rectal cancers. Individual SES derived from parental occupation at birth was associated with altered risk for several cancer sites. This novel methodology can contribute to improved understanding of the role of early-life SES on cancer risk. Cancer Epidemiol Biomarkers Prev; 26(1); 75-84. ©2016 AACR.

Early-Life Socioeconomic Status and Adult Physiological Functioning: A Life Course Examination of Biosocial Mechanisms

Early-Life Socioeconomic Status and Adult Physiological Functioning: A Life Course Examination of Biosocial Mechanisms

Early-life Socio-economic Status and Adult Health: The Role of Positive Affect.

The aim of this paper is to develop a further understanding of the relationship between early-life socio-economic status (SES) and adult health disparities. This was accomplished through evaluation of state indicators of positive and negative affect as mechanisms through which early-life SES was associated with susceptibility to a rhinovirus (i.e. the common cold). Analyses were conducted among 286 adults in a viral challenge study in which participants were exposed to a rhinovirus via nasal drops and cold symptoms were evaluated over a period of 5 days. Participant age, body mass index, sex, education, ethnicity, pre-challenge virus-specific antibody titres and subjective adult SES, along with virus type and season of participation, were included as covariates. Early-life SES was associated with cold incidence through state positive affect, but not state negative affect. In addition, contrast analysis indicated that the indirect effect through state positive affect was stronger than the indirect effect through state negative affect. Findings provide further support for early-life SES being an important variable associated with adult health, and that state self-reported positive affect may be an underlying mechanism associated with susceptibility to rhinoviruses. Copyright © 2016 John Wiley & Sons, Ltd.

Early life growth, socioeconomic status, and mammographic breast density in an urban US birth cohort

PurposeRapid infant and childhood growth has been associated with chronic disease later in life, including breast cancer. Early life socioeconomic status (SES) influences childhood growth, but few studies have prospective measures from birth to consider the effects of early life growth and SES on breast cancer risk. MethodsWe used prospectively measured early life SES and growth (percentile weight change in height and weight between each pair of consecutive time points at birth, 4 months, 1 and 7 years). We performed linear regression models to obtain standardized estimates of the association between 1 standard deviation increase in early life SES and growth and adult mammographic density (MD), a strong risk factor for breast cancer, in a diverse birth cohort (n = 151; 37% white, 38% black, 25% Puerto Rican; average age at mammogram = 42.4). ResultsIn models adjusted for race/ethnicity, prenatal factors, birthweight, infant and childhood growth, and adult body mass index, percentile weight change from 1 year to 7 years was inversely associated with percent MD (standardized coefficient (Stdβ) = −0.28, 95% CI: −0.55 to −0.01), and higher early life SES was positively associated with percent MD (Stdβ = 0.24, 95% CI: 0.04–0.43). Similar associations were observed for dense area, but those estimates were not statistically significant. ConclusionsThese results suggest opposite and independent effects of early life SES and growth on MD.