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Humanfysiologi

A diet rich in fat may be an important precipitating factor of obesity, but studies on this relation have been hampered by the lack of an objective method to assess habitual dietary fat content. We measured 24-h fat oxidation in a respiration chamber in 38 overwight or obese and 35 nonobese women, and used it as an estimate of habitual dietary fat energy (%). After adjustment for confounders, obese women had higher oxidative fat energy than nonobese women [40.2% (37.8-42.6) vs. 36.0% (33.6-38.5), p < 0.02]. Adjusted oxidative fat energy (%) increased with increasing size of fat mass, and this relation suggest that a 10-kg change in fat mass may be caused by a change in dietary fat energy of > or = 1.6%. This objective assessment supports the contention that obese subjects consume a diet with a higher fat content than nonobese individuals, and the high-fat diet may have causal importance for the development and maintenance of obesity.

Medicin, fedme

1. Plasma pancreatic polypeptide, plasma catecholamine, blood glucose, plasma insulin and plasma peptide YY concentrations were studied to assess differences between eight formerly obese and eight never-obese control women during 25 min of sham-feeding (with the sight and smell of an English breakfast) and for 5h after they had ingested the meal (3514 kJ, 50% fat, 35% carbohydrate). The post-obese women had maintained their normal body weight for at least 3 months before the study. 2. The plasma noradrenaline concentration was not different between the groups either during fasting (post-obese women 0.08±0.01 ng/ml versus control women 0.10±0.01 ng/ml) or in the significant postprandial increase (P < 0.001). The plasma adrenaline concentration increased significantly during sham-feeding in the control group from 0.024±0.004 ng/ml to 0.033±0.004 ng/ml (P = 0.02) in contrast with the post-obese women, who had significantly lower plasma concentrations of adrenaline in the fasting state (post-obese 0.016±0.003 ng/ml versus control women 0.024±0.004 ng/ml, P = 0.003), during sham-feeding (post- obese women 0.018±0.002 ng/ml versus control women 0.033±0.004 ng/ml, P=0.003) and in the postprandial increase (P=0.003). The maximal postprandial response concentrations recorded 5h after the meal were 0.025±0.003 ng/ml in post-obese women and 0.035±0.004 ng/ml in control subjects (P = 0.04). There were no significant differences in plasma pancreatic polypeptide, plasma peptide YY, plasma insulin, or blood glucose concentrations between the two groups. 3. The plasma adrenaline concentration is lower in post-obese women in the basal fasting state, during sham-feeding and in response to a meal. These results indicate that post-obese subjects respond differently to food stimulation than normal subjects.

Expansion of the fat stores has been proposed as a prerequisite for increasing fat oxidation in response to a high-fat diet in individuals with a predisposition to obesity. In a cross-sectional design we measured 24-h substrate oxidations on a standardized diet in 38 overweight or obese and 35 nonobese women. Fat oxidation (g/d) was mainly a function of total energy requirements (r = 0.71, P < 0.0001). To account for this we used for further analysis oxidative fat energy (%), a counterpart to dietary fat energy (%). After differences in fat energy of consumed food (%), age, and 24-h energy balance were adjusted for, obese women had higher oxidative fat energy than did nonobese women [40.2% (37.8-42.6) vs 36.0% (33.6-38.5), P < 0.02]. Adjusted oxidative fat energy (%) increased with increasing size of fat mass (r = 0.31, P < 0.01). This relation suggests that a 10-kg change in fat mass may be caused by a change in dietary fat energy of > 1.6% (0.4-2.7%). The study supports the concept that in susceptible individuals the expansion of fat stores is a prerequisite to increase the oxidative fat energy to an amount commensurate with a high percentage of dietary fat energy.

Udgivelsesdato: 1994-Dec, BACKGROUND. A number of studies have demonstrated an association between habitual snoring and cardiovascular morbidity and mortality. Control for the influence of potential confounders has been inadequate. To clarify the issue we examined the association between snoring and future risk of ischaemic heart disease (IHD) and stroke while controlling for the potential influence of major cardio- and cerebrovascular risk factors. METHODS. In all, 804 70 year old males and females were classified according to snoring habits. Alcohol and tobacco consumption, blood pressure, body mass index, social group, plasma lipids (triglycerides, cholesterol, high density lipoprotein), fasting blood glucose, plasma epinephrine and norepinephrine were determined at baseline. RESULTS. Over a 6-year period (1984-1990) 88 suffered an IHD episode, 60 had a stroke and 180 died. A slightly higher stroke incidence was found among snorers (relative risk [RR] = 1.8; (95% confidence interval: 1.1-3.6). When adjustments were made for the above confounders, no associations could be found between snoring and IHD, stroke or all-cause mortality. CONCLUSIONS. In a 70 year old population, snoring is not associated with an increased risk of IHD, stroke or all-cause mortality.

Udgivelsesdato: 1994-Mar, OBJECTIVE. The aim of the study was to evaluate plasma noradrenaline (NA) and plasma adrenalin (A) as predictors of mortality in a population study. SUBJECTS. All subjects were 70 years of age in 1984. They were selected from the National Person Register. Altogether, 804 subjects participated in a comprehensive medical examination. INTERVENTIONS. Plasma NA and A were measured in blood samples collected after the subjects had rested in the supine position for 15 min. The subjects have now been followed for 7 years. MAIN OUTCOME MEASURES. Seven years later, 115 men and 63 women had died. RESULTS. Cox regression analysis showed that the mortality in the male group was positively correlated to plasma NA (P < 0.002) and inversely correlated to forced vital capacity (P < 0.0000) and plasma A (P < 0.02). A positive correlation was obtained between physical working capacity and plasma A. When an index of physical working capacity was included in the Cox regression analysis, both plasma NA and plasma A became insignificant, whereas a strong positive correlation appeared between physical working capacity and survival (P < 0.0000). Those who had low plasma A values in 1984 tended to die from cardiovascular diseases in the follow-up period, whereas in those who died from cancer, plasma A values were similar to those of the general population. CONCLUSIONS. Subjects with high plasma A values had the best survival rate during the 7 year follow-up period, probably because they also had the best physical working capacity. High plasma NA values, as expected, were associated with a reduced survival rate. Measurements of physical working capacity may be an inexpensive measure of probable survival in 70-year-old subjects.

Udgivelsesdato: 1993-Sep, In order to describe the relation between snoring, cardiovascular risk factors, metabolic factors and sympathetitic activity, 804 70-year-old males and females were classified according to snoring habits and life-style factors (alcohol and tobacco consumption), blood pressure, body mass index (BMI), plasma lipids (triglycerides, cholesterol, high density lipoprotein), plasma catecholamines (epinephrine, norepinephrine), fasting blood glucose and glucose tolerance test (1 gram glucose per kg body weight given and blood glucose was measured 1 and 2 hours thereafter) were evaluated in all participants. Self-reported snoring was associated with gender (males showed higher prevalence than females, p < 0.05), alcohol consumption (p < 0.01), BMI (p < 0.001), systolic (p < 0.01) and diastolic (p < 0.05) blood pressure, glucose tolerance test (p < 0.01), plasma norepinephrine (p < 0.05) and partly with tobacco consumption (p = 0.08). No associations were found between snoring and fasting glucose, plasma lipids, plasma epinephrine or in the use of antihypertensive medication. In multivariate analysis, with forced entry of gender, BMI, physical activity, alcohol and tobacco consumption, the relation between snoring and blood pressure ceased; only systolic blood pressure was associated with snoring (p < 0.05). Snoring was still associated with plasma norepinephrine (p < 0.001) and abnormal glucose tolerance (p < 0.001). We conclude that, in a 70-year-old population, snoring is associated with gender, BMI and alcohol consumption. Snores showed higher plasma norepinephrine and abnormal glucose tolerance.

Humanfysiologi