A neglected source of household air pollution: a preliminary, mixed methods study of purposely produced household smoke in Wollo, Ethiopia.

BACKGROUND: Ill health associated with household air pollution (HAP) is increasingly recognized as a public health problem in sub-Saharan Africa. To date, attempts to reduce HAP have focussed on smoke from cooking fires and have ignored traditional cultural practices which generate purposely produced smoke (PPS). This study aimed to investigate PPS prevalence, reasons for use and safety perceptions. METHODS: The study was conducted in Wollo, Ethiopia, and used a mixed methods approach of quantitative surveys (analysed descriptively) and qualitative interviews with householders and healthcare workers (analysed thematically). RESULTS: PPS use was reported by 99% of survey respondents and it was considered a fundamental part of life. Although reasons for use included housekeeping, culture/religion and well-being, coffee ceremony was most commonly cited (44% of respondents). Both householders and healthcare workers appeared to assume PPS is safe, except for people with certain underlying conditions. Healthcare workers felt the lack of evidence of harm from PPS meant there was no justification for intervention. CONCLUSION: This study, the first in-depth study of PPS, has shown its use to be widespread, with many perceived benefits and thus a very important part of local culture in this sample Ethiopian community. Consequently, any public health interventions aimed at reducing HAP in this setting need to consider PPS.

Non-communicable disease clinics in rural Ethiopia: why patients are lost to follow-up.

BACKGROUND: Providing medical care for non-communicable diseases (NCDs) in rural sub-Saharan Africa has proved to be difficult because of poor treatment adherence and frequent loss to follow-up (LTFU). The reasons for this are poorly understood. OBJECTIVE: To investigate LTFU among patients with two different but common NCDs who attended rural Ethiopian health centres. METHOD: The study was based in five health centres in southern Ethiopia with established NCD clinics run by nurses and health officers. Patients with epilepsy or hypertension who were lost to follow-up and non-LTFU comparison patients were identified and traced; a questionnaire was administered enquiring about the reasons for LTFU. RESULTS: Of the 147 LTFU patients successfully located, 62 had died, moved away or were attending other medical facilities. The remaining 85 patients were compared with 211 non-LFTU patients. The major factors associated with LTFU were distance from the clinic, associated costs and a preference for traditional treatments, together with a misunderstanding of the nature of NCD management. CONCLUSIONS: The delivery of affordable care closer to the patients' homes has the greatest potential to address the problem of LTFU. Also needed are increased levels of patient education and interaction with traditional healers to explain the nature of NCDs and the need for life-long management.

David Barker, Buruli ulcer and the epidemiology of a neglected tropical disease.

In 1969, David Barker, his wife and four children moved to Uganda to work at Makerere Medical School in the capital Kampala. During the 1960s, Makerere had become a research and teaching centre with an international reputation based on the work of Trowell, Burkitt, Hutt and many others who had pioneered studies explaining the disease patterns in the West Nile area on the basis of the local climate, nutrition and lifestyle. David Barker was funded by the Medical Research Council to carry out research on a poorly understood disease, Buruli ulcer, joining Scottish surgeon Wilson Carswell, who was later to achieve fame as the role model for Dr Garrigan in Giles Foden's novel The Last King of Scotland.

Size at birth, morning cortisol and cardiometabolic risk markers in healthy Indian children.

OBJECTIVE: Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis may link reduced foetal growth with higher adult chronic disease risk. South Asians have a high prevalence of low birth weight and a thin-fat phenotype, which is associated with subsequent type 2 diabetes and the metabolic syndrome. Altered HPA activity could be one of the pathological processes underlying this link. METHODS: Plasma morning cortisol and corticosteroid-binding globulin (CBG) concentrations were determined in 528 children aged 9·5 years from a prospective birth cohort in India. They had detailed anthropometry at birth, and current measurements of anthropometry, plasma glucose, insulin and lipid concentrations and blood pressure. Insulin resistance (Homeostasis Model Assessment) and insulin secretion (the 30-min insulin increment) were also assessed. RESULTS: None of the birth measurements were associated with cortisol concentrations, but both birth weight (P = 0·03) and length (P = 0·004) were inversely associated with CBG concentrations. Cortisol concentrations were inversely associated with current body mass index (P = 0·02), and positively associated with glucose (fasting: P < 0·001; 30-min: P = 0·002) concentrations, and systolic blood pressure (P = 0·005), but not insulin resistance or the insulin increment. CONCLUSION: Higher morning cortisol is associated with higher cardiometabolic risk markers in Indian children. Although cortisol concentrations did not appear to be related to birth size, small size at birth was associated with higher CBG levels, and may be one of the processes by which foetal undernutrition affects adult health. The findings suggest a need for dynamic testing of HPA axis activity (such as measuring stress responses).

Is susceptibility to chronic rheumatic heart disease determined in early infancy? An analysis of mortality in Britain during the 20th century.

BACKGROUND: The reason why some individuals but not others are susceptible to rheumatic fever and chronic rheumatic heart disease is not understood. Because of the substantial evidence that poverty is an important determinant of the disease and must operate in early life, we have investigated the role of the early environment in an ecological study using 20(th) century mortality as an index of disease prevalence. METHODS: We analysed 37,321 deaths from rheumatic heart disease in England and Wales during 1968-78. We compared the geographical distribution of deaths with previous infant mortality records from 1911 onwards. These records included details of mortality at different ages and from different causes. They also included data on housing and population density. RESULTS: Mortality from rheumatic heart disease showed a strong correlation with past infant mortality that was consistently stronger with postneonatal mortality (deaths from one month to one year) than with neonatal mortality (deaths during the first month of life). Areas with high infant mortality from diarrhoea or bronchitis had the highest subsequent mortality from rheumatic heart disease. Although rheumatic heart disease was linked with early overcrowding, regression analyses suggested that overcrowding could not per se explain the infant mortality associations. CONCLUSIONS: Chronic rheumatic heart disease may have its origins in early infancy. Our findings raise the possibility that susceptibility to rheumatic fever and rheumatic heart disease may be linked with infection in the postneonatal period. Alternatively, they may be explained by the operation of environmental factors that both predispose to infection in infancy and the subsequent liability to heart disease.

Dietary total antioxidant capacity is related to glucose tolerance in older people: the Hertfordshire Cohort Study.

BACKGROUND AND AIMS: Dietary antioxidants may play a protective role in the aetiology of type 2 diabetes. However, observational studies that examine the relationship between the antioxidant capacity of the diet and glucose metabolism are limited, particularly in older people. We aimed to examine the relationships between dietary total antioxidant capacity (TAC) and markers of glucose metabolism among 1441 men and 1253 women aged 59-73 years who participated in the Hertfordshire Cohort Study, UK. METHODS AND RESULTS: Diet was assessed by food frequency questionnaire. Dietary TAC was estimated using published databases of TAC measured by four different assays: oxygen radical absorbance capacity (ORAC), ferric-reducing ability of plasma (FRAP), total radical-trapping antioxidant parameter (TRAP) and trolox equivalent antioxidant capacity (TEAC). Fasting and 120-min plasma glucose and insulin concentrations were measured during a standard 75-g oral glucose tolerance test. In men, dietary TAC estimated by all four assays was inversely associated with fasting insulin concentration and homoeostasis model assessment of insulin resistance (HOMA-IR); with the exception of ORAC, dietary TAC was also inversely related to 120-min glucose concentration. There were no associations with fasting glucose or 120-min insulin concentrations. In women, with the exception of the association between ORAC and 120-min insulin concentration, dietary TAC estimated by all assays showed consistent inverse associations with fasting and 120-min glucose and insulin concentrations and HOMA-IR. These associations were more marked among women with BMI ≥ 30 kg/m(2). CONCLUSION: These findings suggest dietary TAC may have important protective effects on glucose tolerance, especially in older obese women.

Obesity comorbidity in unipolar major depressive disorder: refining the core phenotype.

OBJECTIVE: While a significant body of research has demonstrated high comorbidity rates between depression and obesity, the vast majority of this work has considered depression as a unitary diagnosis. Given that increased appetite and weight gain are highly characteristic of the "atypical" subtype of depression, while classic depression is characterized by decreased appetite and weight loss, it would be important to examine whether increased obesity risk is consistent across the major vegetative subtypes of depression or is limited to the atypical subtype. METHOD: Using data from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), we identified 5,092 US adults with past or current major depression based on DSM-IV-TR criteria and 1,500 gender-matched controls. Each depressed subject was designated as having classic, atypical, or undifferentiated depression based on core vegetative symptoms. Logistic regression models examined rates of current obesity (defined as a current body mass index [kg/m2] > 30) across the 3 depressive subgroups and nondepressed controls, adjusting for demographic differences. To limit the possible effect of current depressive symptoms on observed obesity rates, secondary analyses were completed in individuals with past depression only. RESULTS: Subjects with atypical depression had markedly elevated obesity rates compared to population controls and to other depressed subjects, with corresponding pairwise odds ratios consistently greater than 2.0 (P < .001). In contrast, obesity rates were not significantly different in subjects with classic depression and nondepressed controls. These results were manifest in individuals with either current or past depression and were independent of gender and age. CONCLUSIONS: While many individuals with classic depression will present with obesity due to the high prevalence of both disorders, only atypical depression is associated with an elevated risk of obesity relative to the population at large. Refining the target phenotype(s) for future work on depression and obesity might improve our understanding, prevention, and treatment of this complex clinical problem.

Body size at birth and cardiovascular response to and recovery from mental stress in children.

Cardiovascular (CV) response to mental stress, a predictor of CV disease risk, may be determined already in utero. However, the underlying mechanisms remain unclear, and previous studies have used adult subjects and neglected CV recovery. We investigated 147 girls and 136 boys aged 8 years who underwent the Trier Social Stress Test for children to determine whether body size at birth is associated with CV activity. Blood pressure (BP), electrocardiogram and impedance-derived indices were recorded and analyzed from continuous measurements using Vasotrac APM205A and Biopac MP150 systems. Among girls, lower birth weight was associated with lower baseline systolic BP (SBP) and diastolic BP (DBP) values (1.9 mm Hg and 1.5 mm Hg per 1 s.d. birth weight for gestational age, respectively), higher SBP and DBP response to mental stress (1.6 mm Hg and 1.1 mm Hg per 1 s.d. birth weight for gestational age, respectively), slower BP recovery and overall higher cardiac sympathetic activity. In contrast, among boys lower birth weight was associated with higher baseline levels of SBP (2.1 mm Hg per 1 s.d. birth weight for gestational age) and total peripheral resistance (TPR), overall lower cardiac sympathetic activity, lower TPR response to mental stress and a more rapid BP and cardiac sympathetic recovery. In boys, the associations with baseline levels and cardiac sympathetic activity became significant only after adjusting for current body size. These sex-specific results suggest that individual differences in childhood CV response to and recovery from mental stress may have prenatal origins. This phenomenon may be important in linking smaller body size at birth to adult CV disease.

Self-reported depression and anxiety after prenatal famine exposure: mediation by cardio-metabolic pathology?

Evidence from previous studies suggests an association between prenatal exposure to famine and increased risk for depression. The aim of this study was to investigate whether prenatal exposure to the Dutch famine is associated with self-reported depression/anxiety and whether a potential association is mediated by the presence of cardio-metabolic disease. A total of 819 persons, born as term singletons around the 1944-1945 Dutch famine, filled out the Hospital Anxiety and Depression Scale (HADS) and were asked about their medical history. As indicators of cardio-metabolic disease we included type 2 diabetes (T2D), hypertension and coronary heart disease (CHD). In the total study population, exposure to famine during early gestation was associated with the presence of self-reported mild-to-severe anxiety. Evidence was found for several interactions between exposure in early gestation and sex. Subsequent analyses according to sex showed that men exposed to famine during early gestation scored higher on the HADS depression scale. Self-reported mild-to-severe anxiety symptoms were more prevalent among early exposed men. No such differences were found in women. T2D and hypertension were not correlated with any of the depression and anxiety measures. Adjusting for the presence of CHD did minimally attenuate the size of the reported associations. In conclusion, the present results do not match those previously reported in prenatally famine-exposed individuals. We found only weak evidence for an association between prenatal famine exposure and symptoms of depression and anxiety, which was shown exclusively in men exposed during early gestation.

Maternal BMI, parity, and pregnancy weight gain: influences on offspring adiposity in young adulthood.

CONTEXT: The prevalence of obesity among women of childbearing age is increasing. Emerging evidence suggests that this has long-term adverse influences on offspring health. OBJECTIVE: The aim was to examine whether maternal body composition and gestational weight gain have persisting effects on offspring adiposity in early adulthood. DESIGN AND SETTING: The Motherwell birth cohort study was conducted in a general community in Scotland, United Kingdom. PARTICIPANTS: We studied 276 men and women whose mothers' nutritional status had been characterized in pregnancy. Four-site skinfold thicknesses, waist circumference, and body mass index (BMI), were measured at age 30 yr; sex-adjusted percentage body fat and fat mass index were calculated. MAIN OUTCOME MEASURE: Indices of offspring adiposity at age 30 yr were measured. RESULTS: Percentage body fat was greater in offspring of mothers with a higher BMI at the first antenatal visit (rising by 0.35%/kg/m2; P<0.001) and in offspring whose mothers were primiparous (difference, 1.5% in primiparous vs. multiparous; P=0.03). Higher offspring percentage body fat was also independently associated with higher pregnancy weight gain (7.4%/kg/wk; P=0.002). There were similar significant associations of increased maternal BMI, greater pregnancy weight gain, and parity with greater offspring waist circumference, BMI, and fat mass index. CONCLUSIONS: Adiposity in early adulthood is influenced by prenatal influences independently of current lifestyle factors. Maternal adiposity, greater gestational weight, and parity all impact on offspring adiposity. Strategies to reduce the impact of maternal obesity and greater pregnancy weight gain on offspring future health are required.

Insulin-requiring diabetes in Ethiopia: associations with poverty, early undernutrition and anthropometric disproportion.

BACKGROUND/OBJECTIVES: Most insulin-requiring diabetes patients in Ethiopia have an atypical form of the disease, which resembles previous descriptions of malnutrition-related diabetes. As so little is known about its aetiology, we have carried out a case-control study to evaluate its social and nutritional determinants. SUBJECTS/METHODS: Men and women with insulin-requiring diabetes (n=107), aged 18-40 years, were recruited in two centres, Gondar and Jimma, 750 km northwest and 330 km southwest of the capital, Addis Ababa, respectively. Controls of similar age and sex (n=110) were recruited from patients attending other hospital clinics. RESULTS: Diabetes was strongly associated with subsistence farming, odds ratio=3.5 (95% confidence interval: 1.5-7.8) and illiteracy/low levels of education, odds ratio=4.0 (2.0-8.0). Diabetes was also linked with a history of childhood malnutrition, odds ratio=5.5 (1.0-29.0) the mother's death during childhood, odds ratio=3.9 (1.0-14.8), and markers of poverty including poorer access to sanitation (P=0.004), clean water (P=0.009), greater overcrowding (P=0.04), increased distance from the clinic (P=0.01) and having fewer possessions (P=0.01). Compared with controls, people with diabetes had low mid upper arm circumference, body mass index (BMI) and fat/lean body mass (P<0.01). In addition, men with the disease tended to be shorter, were lighter (P=0.001), with reduced sitting height (P=0.015) and reduced biacromial (P=0.003) and bitrochanteric (P=0.008) diameters. CONCLUSIONS: Insulin-requiring diabetes in Ethiopia is strongly linked with poor education and markers of poverty. Men with the disease have associated disproportionate skeletal growth. These findings point towards a nutritional aetiology for this condition although the nature of the nutritional deficiency and its timing during growth and development remains obscure.

Insulin-requiring diabetes in rural Ethiopia: should we reopen the case for malnutrition-related diabetes?

AIMS/HYPOTHESIS: We evaluated the incidence of insulin-requiring diabetes in a rural area of sub-Saharan Africa. METHODS: Health surveillance data from a chronic disease programme in two zones of Ethiopia, Gondar and Jimma, were studied. The two zones have a population of more than 5,000,000 people. RESULTS: In Gondar Zone (1995-2008) and Jimma Zone (2002-2008) 2,280 patients presented with diabetes, of whom 1,029 (45%) required insulin for glycaemic control at diagnosis. The annual incidence of insulin-requiring diabetes was 2.1 (95% CI 2.0-2.2) per 100,000 and was twice as high in men (2.9 per 100,000) as in women (1.4 per 100,000). In both sexes incidence rates peaked at the age of 25 to 29 years. Incidence rates in the urban areas of Gondar and Jimma were five times higher than in the surrounding rural areas. Patients with insulin-requiring diabetes from rural and urban areas had a very low BMI and most were subsistence farmers or unemployed. CONCLUSIONS/INTERPRETATION: The typical patient with diabetes in rural Ethiopia is an impoverished, young adult male with severe symptoms requiring insulin for glycaemic control. The low incidence rates in rural compared with urban areas suggest that many cases of this disease remain undiagnosed. The disease phenotype encountered in this area of Africa is very different from the classical type 1 diabetes seen in the West and most closely resembles previous descriptions of malnutrition-related diabetes, a category not recognised in the current WHO Diabetes Classification. We believe that the case for this condition should be reopened.

The relationship between depression and diabetes mellitus: findings from the Hertfordshire Cohort Study.

AIMS: To assess the relationship between depression scores and diabetes, glucose and insulin in a cross-sectional population-based study. METHODS: One thousand, five hundred and seventy-nine men and 1418 women from the Hertfordshire Cohort Study were assessed for diabetes. Plasma glucose and insulin concentrations were measured at 0, 30 and 120 min during a standard 75-g oral glucose tolerance test. Depressive and anxiety symptoms were measured using the Hospital Anxiety and Depression Scale (HADS). RESULTS: Overall, 431 (14.6%) were diagnosed with diabetes [232 men (14.9%) and 199 women (14.3%)]. One hundred and eight (47%) men and 74 (37%) women had known diabetes. The remainder were previously undiagnosed. Fifty-nine (3.7%) men and 65 (4.6%) women had possible depression (HAD-D scores 8-10) and 17 (1.1%) men and 20 (1.4%) women had probable depression (HAD-D scores > or = 11). Probable depression was associated with an adjusted odds ratio for diabetes of 3.89 [95% confidence interval (CI) 1.28-11.88] in men and 1.51 (95% CI 0.47-4.84) in women. In men without previously diagnosed diabetes, fasting insulin (P = 0.035), 2-h glucose concentrations (P = 0.028) and insulin resistance (P = 0.032) were significantly associated with HAD-D scores. With the exception of 2-h glucose concentrations (P = 0.034), the associations were not significant in women. CONCLUSIONS: These data support the hypothesis that depression may increase the risk for diabetes. The relationship between depression score and metabolic variables extends across the whole population and is not confined to those with either diagnosed depression or diabetes. This relationship should lead clinicians to consider screening for diabetes in those with depression and vice versa.

Transgenerational effects of prenatal exposure to the Dutch famine on neonatal adiposity and health in later life.

OBJECTIVE: Maternal undernutrition during gestation is associated with increased metabolic and cardiovascular disease in the offspring. We investigated whether these effects may persist in subsequent generations. DESIGN: Historical cohort study. SETTING: Interview during a clinic or home visit or by telephone. POPULATION: Men and women born in the Wilhelmina Gasthuis in Amsterdam between November 1943 and February 1947. METHODS: We interviewed cohort members (F1) born around the time of the 1944-45 Dutch famine, who were exposed or unexposed to famine in utero, about their offspring (F2). MAIN OUTCOME MEASURES: Birthweight, birth length, ponderal index and health in later life (as reported by F1) of the offspring (F2) of 855 participating cohort members, according to F1 famine exposure in utero. RESULTS: F1 famine exposure in utero did not affect F2 (n = 1496) birthweight, but, among the offspring of famine-exposed F1 women, F2 birth length was decreased (-0.6 cm, P adjusted for F2 gender and birth order = 0.01) and F2 ponderal index was increased (+1.2 kg/m(3), P adjusted for F2 gender and birth order = 0.001). The association remained unaltered after adjusting for possible confounders. The offspring of F1 women who were exposed to famine in utero also had poor health 1.8 (95% CI 1.1-2.7) times more frequently in later life (due to miscellaneous causes) than that of F1 unexposed women. CONCLUSIONS: We did not find transgenerational effects of prenatal exposure to famine on birthweight nor on cardiovascular and metabolic disease rates. F1 famine exposure in utero was, however, associated with increased F2 neonatal adiposity and poor health in later life. Our findings may imply that the increase in chronic disease after famine exposure in utero is not limited to the F1 generation but persists in the F2 generation.

Association of adult height and leg length with fasting plasma cortisol concentrations: evidence for an effect of normal variation in adrenocortical activity on growth.

We have evaluated the relationship between activity of the hypothalamic-pituitary-adrenal (HPA) axis and adult height in adults recruited from the UK Hertfordshire Cohort Study. In a sample of 1,354 individuals, we found that height fell by 0.67 cm (95% CI 0.34-1.0) per SD (114 nmol/l) increase in fasting plasma cortisol concentrations. The association was continuous across the range of cortisol concentrations and was independent of the levels of corticosteroid binding globulin. It was of similar magnitude in men and women. In a subsample of the study available data on standing and sitting height was used to estimate trunk and leg length. Fasting plasma cortisol concentrations were found to have a much greater impact on leg length than trunk length. These findings suggest that physiological variations in adrenocortical glucocorticoid secretion in humans affect adult height. They also raise the possibility that the HPA axis may be involved in mediating resource allocation decisions and trade-offs during development perhaps by limiting physical growth to enable other competing processes.

Childhood growth and cardiovascular reactivity to psychological stressors in late adulthood.

OBJECTIVE: Specific childhood growth patterns relate to risk of cardiovascular (CV) disease later in life, but the underlying mechanisms are unclear. We studied whether CV reactivity, a predictor of CV disease risk, is associated with childhood growth trajectories. METHODS: A total of 144 (77 women and 67 men) participants of the Helsinki Birth Cohort Study born 1934-1944, whose height and weight were recorded repeatedly during the first 11 years, underwent the Trier Social Stress Test at the average age of 63 years. Beat-to-beat blood pressure was monitored via noninvasive finger photoplethysmograph (Finometer), and CV reactivity scores were determined as the mean increment from baseline. RESULTS: In both women and men, systolic blood pressure (SBP) reactivity increased by 3.8 mmHg (95% CI 0.8-6.9) and diastolic BP (DBP) reactivity by 1.4 mmHg (95% CI 0.0-2.8) for every standard deviation increase in gain in body mass index (kg m(-2)) between 7 and 11 years. By contrast, effects of height gain were dissimilar between sexes. In women, higher DBP reactivity was associated with a slow gain in height between 0 and 2 years, whilst in men higher SBP reactivity was associated with a slow gain in height between 2 and 7 years, which was preceded by a more rapid gain in height between 0 and 2 years. Adjusting for adult body size, body size at birth or childhood socio-economic status did not change the results. CONCLUSIONS: We found that growth during childhood is associated with CV reactivity to stress later in adulthood. Early life programming of CV reactivity may partly underlie the link between early growth and CV disease.

Grip strength and the metabolic syndrome: findings from the Hertfordshire Cohort Study.

INTRODUCTION: Sarcopenia, the loss of muscle mass and strength with age, is significantly associated with type 2 diabetes in older people. AIM: To determine whether there is a relationship between grip strength and features of the metabolic syndrome. DESIGN: Cross-sectional study. METHODS: Data were collected on grip strength, fasting glucose, triglycerides and HDL cholesterol, blood pressure, waist circumference and 2 h glucose after an oral glucose tolerance test, in a population-based sample of 2677 men and women aged 59-73 years. RESULTS: In men and women combined, a standard deviation (SD) decrease in grip strength was significantly associated with higher: fasting triglycerides (0.05 SD unit increase, 95%CI 0.02-0.09, p = 0.006); blood pressure (OR 1.13, 95%CI 1.04-1.24, p = 0.004); waist circumference (0.08 SD unit increase, 95%CI 0.06-0.10, p < 0.001); 2 h glucose (0.07 SD unit increase, 95%CI 0.03-0.11, p = 0.001) and HOMA resistance (0.05 SD unit increase, 95%CI 0.01-0.09, p = 0.008), after adjustment for gender, weight, age, walking speed, social class, smoking habit and alcohol intake. Lower grip strength was also significantly associated with increased odds of having the metabolic syndrome according to both the ATPIII (OR 1.18, 95%CI 1.07-1.30, p < 0.001) and IDF definitions (OR 1.11, 95%CI 1.01-1.22, p = 0.03). DISCUSSION: Our findings suggest that impaired grip strength is associated with the individual features, as well as with the overall summary definitions, of the metabolic syndrome. The potential for grip strength to be used in the clinical setting needs to be explored.

Differential effects of fatness, fitness and physical activity energy expenditure on whole-body, liver and fat insulin sensitivity.

AIMS/HYPOTHESIS: The relative contributions of fitness (maximal oxygen uptake), physical activity energy expenditure (PAEE) and fatness to whole-body, liver and fat insulin sensitivity is uncertain. The aim of this study was to determine whether fitness and PAEE are associated with whole-body, liver and fat insulin sensitivity independently of body fat. MATERIALS AND METHODS: We recruited 25 men (mean [SD] age 53 [6] years). Whole-body (M value) and liver (percentage suppression of endogenous glucose output) insulin sensitivity were estimated using a hyperinsulinaemic-euglycaemic clamp. Insulin sensitivity in fat (insulin sensitivity index for NEFA) was estimated during an OGTT. Total and truncal fat were measured by dual-energy X-ray absorptiometry, fitness by treadmill, and PAEE (n = 21) by 3 day heart rate monitoring and Baecke questionnaire. RESULTS: In univariate analyses, fatness was strongly associated with insulin sensitivity (whole-body, liver and fat). Fitness was associated with whole-body (r = 0.53, p < 0.007) and liver (0.42, p = 0.04) insulin sensitivity, while PAEE was associated with liver insulin sensitivity (r = 0.55, p = 0.01). Regression models were established to describe associations between fatness, fitness and physical activity and measures of insulin sensitivity (whole-body, fat and liver) as outcomes. Only fatness was independently associated with whole-body insulin sensitivity (B coefficient -0.01, p = 0.001). Fitness was not associated with any outcome. Only PAEE was independently associated with liver insulin sensitivity (B coefficient 13.5, p = 0.02). CONCLUSIONS/INTERPRETATION: Fatness explains most of the variance in whole-body insulin sensitivity. In contrast, PAEE explains most of the variance in liver insulin sensitivity.

Programming of the stress response: a fundamental mechanism underlying the long-term effects of the fetal environment?

There is a large body of evidence which suggests that an adverse fetal environment results in a heightened biobehavioral response to stress, with increased activity of the classical mediators of the stress response, including the hypothalamic-pituitary adrenal axis and autonomic nervous system. Although this has been amply demonstrated in animal experiments, several recent studies suggest that the same processes operate in human populations and may have important consequences for health. The evidence suggests that an adverse early environment or markers of an adverse environment such as low birth weight are linked with long-term alterations in these neuroendocrine systems. However, these studies also demonstrate that there is a considerable degree of heterogeneity in the responses observed which appear to depend on a variety of factors such as the nature or timing of the adverse exposure as well as the gender of the offspring. The mediators of these classical neuroendocrine responses such as cortisol and catecholamines are biologically potent and may directly influence disease susceptibility by means of their effects on metabolism and the vasculature. However, lifelong changes in the set point of these neuroendocrine systems in response to the early environment may also direct the course of development during fetal life, infancy and childhood towards the generation of a phenotype adapted for the adult environment predicted by the clues available during fetal life. This has biological advantages if the actual adult environment turns out to be appropriate for the phenotype. However, ill health may occur if the phenotype is not well matched to the actual environment encountered in adult life.

Cardiovascular reactivity to psychological stressors in late adulthood is predicted by gestational age at birth.

The relationships of body size and gestational age at birth with adult blood pressure (BP) are relatively modest compared to their stronger associations with cardiovascular disease. BP reactivity is a strong predictor of cardiovascular morbidity, and it is possible that reactivity, rather than resting level, is determined in utero. We investigated whether body size and gestational age at birth predict BP reactivity during experimentally induced psychosocial stress in late adulthood. A total of 73 men and 80 women born after 36 weeks' gestation in Helsinki, Finland, during 1934-1944 underwent the Trier Social Stress Test (TSST); a standardized psychosocial stress test consisting of a public speech and an arithmetic task. Changes in BP were monitored continuously by a non-invasive finger photoplethysmography (Finometer, FMS, Amsterdam, The Netherlands). The results showed that the most robust early determinant of BP reactivity was gestational age; however, with opposite relationships between the sexes (P for interaction <0.001). A 1-week increase in gestational age was associated with a 3.1 mm Hg (95% confidence interval (CI), 0.2 to 6.0) and 1.2 mm Hg (95% CI, -0.1 to 2.6) decreases in systolic and diastolic BP reactivity in women, but with 5.2 mm Hg (95% CI, 1.9 to 8.4) and 2.3 mm Hg (95% CI, 0.9 to 3.8) increases in men. In conclusion, normal variation in gestational age at birth predicts cardiovascular stress reactivity in later adulthood. Given that hypothalamic-pituitary-adrenal axis contributes to the regulation of autonomic nervous system function and the timing of parturition, and shows well-established sex differences, we speculate a role for early programming of this axis in explaining the findings.