Tomo Kanda

Exercise training and autonomic nervous system activity in obese individuals

PURPOSE This study was designed to investigate the effects of 12 wk of exercise training on autonomic nervous system (ANS) in 18 obese middle-aged men (N = 9) and women (N = 9) (age: 41.6 +/- 1.2 yr; BMI: 27.3 +/- 0.4 kg x m(-2); %fat: 29.6 +/- 1.3%, mean +/- SE). METHODS Each subject participated in an aerobic exercise training at anaerobic threshold (AT), consisting of 30 min/session, 3 times/wk, for 12 consecutive weeks. The ANS activities were assessed by means of power spectral analysis of heart rate variability (HRV) at resting condition before, at 5 wk, and after the exercise program. RESULTS The exercise training resulted in a significant decrease in body mass, BMI, and % fat (P < 0.01) but not in lean body mass (P > 0.05) together with a significant increase in the AT VO2 (P < 0.01). Our power spectral data indicated that there were significant increases in the low-frequency component associated with the sympathovagal activity (0.03--0.15 Hz, 348.5 +/- 66.8 vs 694.7 +/- 91.5 ms(2), P < 0.01), the high-frequency vagal component (0.15--0.4 Hz, 146.3 +/- 30.4 vs 347.7 +/- 96.5 ms(2), P < 0.05), and the overall autonomic activity as evaluated by total power (0.03--0.4 Hz, 494.8 +/- 88.5 vs 1042.4 +/- 180.9 ms(2), P < 0.01) of HRV after the training. CONCLUSIONS Twelve weeks of exercise training has significantly improved both the sympathetic and parasympathetic nervous activities of the obese individuals with markedly reduced ANS activity, suggesting a possible reversal effect of human ANS functions. These favorable changes may also have an influence on the thermoregulatory control over the obesity.

Effects of dietary intake of soy protein and isoflavones on cardiovascular disease risk factors in high risk, middle-aged men in Scotland.

Objective: To investigate the effects of soy protein and isoflavones on blood pressure (BP) and cholesterol levels among high risk middle-aged Scottish men. Design: A randomized, double-blind, placebo-controlled, parallel-group dietary intervention study Setting: Inhabitants on Isles of Lewis and Harris in Scotland Subjects: Sixty-one men with relatively higher BP and/or total cholesterol (TC) levels aged 45 to 59 went through the dietary intervention. Intervention: Diets containing at least 20 g of soy protein and 80 mg of isoflavones were compared to the placebo diets. Intervention period was 5 weeks duration. Results: Significant difference was found in 24-hour urinary isoflavone excretion between the two groups after intervention. Significant reductions from the baselines were observed in systolic BP (SBP) and diastolic BP (DBP), TC and non-high density lipoprotein cholesterol (non-HDL-C) in the soy-containing diet group, but not in the olive oil containing active placebo group. Significant increases in high density lipoprotein cholesterol (HDL-C) were observed in both groups. Conclusion: Dietary intakes of soy protein (at least 20 g) and isoflavones (at least 80 mg) for 5 weeks would be effective in reducing CHD risk among high-risk, middle-aged men.

Cardiovascular risk factors in Tanzania: a revisit

In this assessment of cardiovascular risk factors, we examined the prevalence of selected risk factors according to the World Health Organisation (WHO) CARDIAC Study protocol and compared them with a similar study conducted more than a decade ago. The survey was carried out in Dar es Salaam (D, urban), Handeni (H, rural) and Monduli (Mo, semi-nomadic area). Subjects aged 47-57 were recruited randomly for blood pressure and anthropometrical measurements, 24 h urine collection and blood sampling. A structured questionnaire was used to obtain dietary information. The 1998 survey studied 446 subjects, while the 1987 survey included 496 men and women. The measured weight, body mass index (BMI) and prevalence of obesity (BMI > or = 30 kg/m(2)) increased significantly among women in the 1998 survey in rural Handeni and urban Dar. The overall prevalence of obesity was higher for women in the most recent survey (22.8%, P < 0.0001). Diastolic blood pressure (DBP) was higher in the most recent survey for women in Handeni. The overall prevalence of hypertension (blood pressure > 160/95 mmHg, or antihypertensive drug use), rose to 41.1% in 1998, (P < 0.001) for men and to 38.7% (P < 0.05) for women. The mean total serum cholesterol and prevalence of hypercholesterolaemia increased significantly in the most recent survey in the three studied areas. The overall prevalence of hypercholestrolaemia (serum cholesterol > 5.2 mmol/l) was higher in the 1998 survey for both men (21.8%, P < 0.0001) and women (54.0%, P < 0.0001). The mean HDL cholesterol increased significantly in the most recent survey, with a significant reduction in the mean atherogenic index, though these were still at higher levels (men 5.8, P < 0.0001; women 5.1, P < 0.0001 vs. 1987). A strong positive correlation was observed between blood pressure (SBP and DBP) and body mass index, total serum cholesterol and sodium to potassium ratio. These data suggest that for the past decade there has been an increase in the mean levels and prevalence of selected cardiovascular risk factors in Tanzania.

Nutritional variation and cardiovascular risk factors in Tanzania--rural-urban difference.

OBJECTIVE To assess the relationship between dietary factors and cardiovascular (CVD) risk factors in middle-aged men and women, in urban, rural and pastoral settings in Tanzania. DESIGN Cross-sectional epidemiological study designed according to the protocol of the World Health Organisation (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) study. SETTING Three centres in Tanzania, namely Dar es Salaam (urban), Handeni (rural) and Monduli (pastoral population). SUBJECTS The subjects, aged 47-57 years, were recruited randomly from administrative lists available from each centre. OUTCOME MEASURES Blood pressure (BP) was measured using a centrally calibrated automatic BP machine (Khi machine). Dietary history of the participants was obtained using a standard questionnaire designed on the basis of a seven-day recall system. Height, weight, serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDLC), haemoglobin A1c, sodium, potassium and magnesium were measured. RESULTS The prevalence of hypertension (BP > or = 140/90 mmHg or antihypertensive drug use), obesity (body mass index (BMI) > or = 30 kg/m2) and hypercholesterolaemia (TC > 5.2 mmol/l) were lowest in the rural area. Consumption of green vegetables, milk, coconut milk, meat, and fish varied significantly between the three areas. Important determinants for BP among men were BMI (p < 0.001), and salt intake (p < 0.05). Among women, TC (p < 0.05), age (p < 0.05), BMI (p < 0.001) and coconut milk consumption (p < 0.001) were important BP determinants. Salt intake was positively associated with systolic BP (SBP) and diastolic BP (DBP) in men but not among women (both SBP and DBP p < 0.05 respectively). Dietary determinants of serum TC were meat, fish and green vegetable consumption. CONCLUSION Differences in dietary habits contributed significantly to the urban-rural-pastoral variations in CVD risk pattern in Tanzania.

The relation of oxidative DNA damage to hypertension and other cardiovascular risk factors in Tanzania.

Objectives To clarify the mechanism of involvement of oxidative stress in hypertensives, we investigated the relationship between the marker of oxidative DNA damage, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), and cardiovascular risk factors, such as hypertension and serum glycosylated hemoglobin (HbA1c), among Tanzanians aged 46–58 years who were not on antihypertensive medication. Design and methods Sixty subjects (males/females, 28/32) were selected randomly from the subjects who completed a 24h urine collection in our epidemiological study at Dar es Salaam, Tanzania in 1998. The subjects were divided into two groups, hypertensive subjects (systolic blood pressure (SBP) ⩾ 140 mmHg and/or diastolic blood pressure (DBP) ⩾90 mmHg) and normotensive subjects (SBP <140 mmHg and DBP <90 mmHg) or hyperglycemic subjects (HbA1c ⩾ 6.0%) and normoglycemic subjects (HbA1c< 6.0%). Biological markers from urine and blood were analyzed centrally in the WHO Collaborating Center. Results The mean levels of HbA1c and 8-OHdG were significantly higher in the hypertensive subjects than in the normotensive subjects (P < 0.05). Urinary 8-OHdG was significantly higher in hyperglycemic subjects than in normoglycemic subjects. HbA1c was positively correlated with the 24-h urinary 8-OHdG excretions (r = 0.698, P < 0.0001). Conclusions These findings suggest oxidative DNA damage is increased in hypertensive subjects, and there is a positive correlation between the level of blood glucose estimated as HbA1c and oxidative DNA damage. Hyperglycemia related to insulin resistance in hypertension in Tanzania is associated with increased urinary 8-OHdG.

Arterial pulse wave velocity and risk factors for peripheral vascular disease

Abstract Non-invasive measurement of arterial pulse wave velocity (PWV) is used to diagnose peripheral vascular disease. We examined the relationship between PWV and risk factors related to peripheral vascular disease [body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), atherogenic index (AI) and blood glucose (GLU)] in 45 healthy male volunteers, aged 25–85 years. The correlation coefficient of PWV with age was r=0.46, and the correlation coefficients of PWV with DBP, AI and GLU were r=0.71, 0.56, and 0.22, respectively (P < 0.05). Multiple linear regression analysis revealed that 67% of the variance in PWV could be accounted for by these three variables. The relative contributions of DBP, AI and GLU to PWV were 66%, 26% and 8%, respectively. To test the applicability of PWV for clinical use, a multiple regression equation of PWV derived from these three variables was then applied to male patients with hypertension (n=53), hyperlipidaemia (n=35) or hyperglycaemia (n=39). The results suggest that the multiple regression equation of PWV is an indicator that discriminates between these patient categories and healthy men.

Prevalence of overweight and hypertension in Tanzania: Special emphasis on resting energy expenditure and leptin

1. In the present study we investigated the difference in the distribution of selected cardiovascular disease risk factors among three middle‐aged Tanzanian populations with different lifestyles.1. The accuracy of measurements of flow rate and concentrations of O2 and CO2 in expiratory gas by indirect calorimetry (IC) using paediatric and adult circuits were assessed by mass spectrometry and a pneumotachogram, which have been proven as the most reliable instruments for these purposes. 2. In the paediatric circuit, all measurements were demonstrated to be reliable: error rates for flow rate, O2 concentration and CO2 concentration were +3.13, +2.66 and -6.63%, respectively. All were within the 10%, which is acceptable as a biological error. 3. However, in the adult circuit of IC, all measurements were reliable except for measurements of CO2 concentration: error rates for flow rate, O2 concentration and CO2 concentration were +2.82, +1.64 and +11.42%, respectively. 4. A fluctuation phenomenon of expiratory gas concentration was observed only in IC. Mass spectrometry did not show this phenomenon. This phenomenon seems to be derived from the IC machine itself.