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.     

Risk of HIV infection attributable to oral sex among men who have sex with men and in the population of men who have sex with men

We examined HIV infection and estimated the population-attributable risk percentage (PAR%) for HIV associated fellatio among men who have sex with other men (MSM). Among 239 MSM who practised exclusively fellatio in the past 6 months, 50% had three partners, 98% unprotected; and 28% had an HIV-positive partner; no HIV was detected. PAR%, based on the number of fellatio partners, ranges from 0.10% for one partner to 0.31% for three partners. The risk of HIV attributable to fellatio is extremely low.     

Birthsize, gestational age and adrenal function in adult life: studies of dexamethasone suppression and ACTH1-24 stimulation

OBJECTIVE: Several studies show that low birthweight is associated with long-term alterations in the function of the hypothalamic-pituitary-adrenal axis (HPAA). We recently reported that the relationship between birthweight and fasting serum cortisol concentrations differed according to the gestational age of the babies, suggesting that both hypercortisolism and hypocortisolism could be a consequence of impaired fetal growth. We have now extended these findings by examining the relationship between birthweight, gestational age and tests of adrenal suppression and stimulation. DESIGN: Prospective birth cohort study. SUBJECTS AND METHODS: We studied 165 women (mean age 71.3 Years) born at term in Helsinki, Finland, between 1924 and 1933, whose body size and gestational age at birth were recorded. These women underwent an overnight 0.25 mg dexamethasone suppression test followed by a 1 microg ACTH(1-24) stimulation test. RESULTS: In all women combined, low birthweight was associated with lower total (P=0.03) and free (P=0.02) cortisol concentrations following dexamethasone. However, these relationships were dependent on gestational age at birth, interactions between the effects of birth size and gestational age on dexamethasone responsiveness being statistically significant. To demonstrate these interactions, we divided the study population into two groups according to gestational age. In subjects born at 40 weeks of gestation or more, low birthweight was strongly associated with enhanced dexamethasone suppression (P=0.003 for total and P=0.0004 for free cortisol), while in subjects born before 40 weeks of gestation there was no association. There was, however, no correlation between birth size and the adrenal response to ACTH(1-24). CONCLUSIONS: These findings reinforce our suggestions that events during prenatal life may lead to both up-regulation and down-regulation of the HPAA.     

Effects of size at birth and childhood growth on the insulin resistance syndrome in elderly individuals

Aims/hypothesis: A study of 7086 men and women born in Helsinki, Finland, has shown that the development of Type II (non-insulin-dependent) diabetes mellitus is associated with low birth weight followed by accelerated gain in height and weight during childhood and with high maternal BMI but the processes which underlie these associations are largely not known. Methods: We carried out standard oral glucose tolerance tests, and measured plasma insulin and proinsulin, serum lipid concentrations and blood pressure in 474 patients from the Helsinki cohort. Results: We used four indices of insulin resistance: fasting and 2-h plasma insulin, and fasting proinsulin and 32–33 split proinsulin concentrations. These were associated with small body size at birth and during childhood, rapid growth in height and low maternal BMI. Conclusion/interpretation: Insulin resistance and Type II diabetes share common associations with retarded fetal growth and accelerated growth during childhood. They are dissimilar, however, in that insulin resistance is associated with thinness in childhood and low maternal BMI, while Type II diabetes is associated with high BMI in childhood and high maternal BMI. [Diabetologia (2002) 45: 342–348] Received: 23 August 2001 and in revised form: 2 November 2001     

Testing the fetal origins hypothesis in twins: the Birmingham twin study

Aims/hypothesis. To test whether the link between birthsize and raised blood pressure or glucose tolerance is due to genetic or intrauterine factors, we studied whether differences in birthweight between pairs of monozygous and dizygous twins are associated with adult differences in blood pressure and glucose tolerance.¶Methods. A sample of 58 monozygous and 140 dizygous twins were identified from a register of births in Birmingham, United Kingdom, between 1950 and 1954. The twins had their blood pressure measured and underwent an oral glucose tolerance test.¶Results. There were no statistically significant associations between birthweight, length or ponderal index, and either blood pressure or glucose tolerance in the twins. Although there were substantial within-pair differences in birthweight between monozygous and dizygous twin pairs, these differences did not correlate with the adult outcomes. Monozygous correlations, however, for both blood pressure and glucose tolerance were statistically significantly higher than dizygous correlations and a quantitative genetic model suggested statistically significant heritability for these traits. In contrast correlations of birthsize were similar in monozygous and dizygous pairs suggesting only a small genetic component in determining fetal size.¶Conclusion/interpretation. Our results show that birthsize in twins does not predict adult blood pressure or glucose tolerance. We also suggest that shared genetic determinants for fetal growth and adult outcomes are not likely to be prevalent or powerful. [Diabetologia (2001) 44: 33–39]     

Type 2 (non-insulin-dependent) diabetes mellitus,hypertension and hyperlipidaemia (syndrome X): relation to reduced fetal growth

Summary Two follow-up studies were carried out to determine whether lower birthweight is related to the occurrence of syndrome X — Type 2 (non-insulin-dependent) diabetes mellitus, hypertension and hyperlipidaemia. The first study included 407 men born in Hertfordshire, England between 1920 and 1930 whose weights at birth and at 1 year of age had been recorded by health visitors. The second study included 266 men and women born in Preston, UK, between 1935 and 1943 whose size at birth had been measured in detail. The prevalence of syndrome X fell progressively in both men and women, from those who had the lowest to those who had the highest birthweights. Of 64-year-old men whose birthweights were 2.95 kg (6.5 pounds) or less, 22% had syndrome X. Their risk of developing syndrome X was more than 10 times greater than that of men whose birthweights were more than 4.31 kg (9.5 pounds). The association between syndrome X and low birthweight was independent of duration of gestation and of possible confounding variables including cigarette smoking, alcohol consumption and social class currently or at birth. In addition to low birthweight, subjects with syndrome X had small head circumference and low ponderal index at birth, and low weight and below-average dental eruption at 1 year of age. It is concluded that Type 2 diabetes and hypertension have a common origin in sub-optimal development in utero, and that syndrome X should perhaps be re-named the small-baby syndrome.     

Donor motivation in Xi’an,China: comparison with Canadian donors

Background and Objectives In China, paid donation is prohibited by law. There is little literature assessing donor motivation in China, and comparison with western countries such as Canada is important in understanding the application of Western literature. We compared motivational factors in donors from the city of Xi’an, China, with Canadian donors matched for age, sex and donation status. Materials and Methods A total of 218 donors in Xi’an completed an interview about motivation as did 218 Canadian donors matched for age, sex and donation status. Frequencies and percentages of responses to questions were tabulated and compared using the Chi‐squared test. Results Donors in Xi’an and Canada felt a personal responsibility to donate blood (81·2% vs. 78·0%, P = 0·2057), but Xi’an donors were more likely to consider blood donation a social responsibility (81·7% vs. 45·2%, P < 0·0001). Xi’an donors more often believed that society views donation as a normal activity (98·6% vs. 48·4%, P < 0·0001) and that the social atmosphere promotes donation (90·3% vs. 53·5%, P < 0·0001) and saw greater health benefit (52·3% vs. 12·5%, P < 0·0001). Most Xi’an donors believed in balance between their life force (Qi) and blood (86·7% vs. 49·8%, P < 0·0001) but did not believe blood lost from donating would affect this (0·5% vs. 3·8%, P = 0·01). Conclusion While traditional Chinese beliefs may not be seen as a barrier among people in Xi’an who donate blood, blood donation is seen differently than by Canadian donors. There is a need for more research specific to China to tailor recruitment strategies.