Published papers

1980年に心血管系疾患・癌(メラノーマ以外の皮膚癌を除く)に罹患していなかったペンシルバニア大学卒業生女性1123例を1995年まで追跡し,高齢女性における身体活動量と総死亡率との関連を検討した.身体活動量は総死亡率と負の関連が認められた.特に,1日に12ブロック(1マイル相当)以上歩行していた女性は追跡期間中死亡する危険度が4ブロック未満の女性に比し31%低かった.高齢女性において,中等度の強度の身体活動でも死亡率低下につながることが示唆された

To explore the physiologic limit of left ventricular (LV) enlargement, we performed echocardiography and air displacement plethysmography to respectively assess LV dimension and function and the body composition of Japanese professional sumo wrestlers. After excluding subjects with cardiovascular disease, hypertension, plasma brain natriuretic peptide (BNP) > or =17.9 pg/ml, diabetes mellitus, or asthma, 331 subjects (mean +/- SD age, 21.6 +/- 3.7 years; height 179.2 +/- 5.3 cm; weight 1,17.9 +/- 21.5 kg; percent fat, 29.6 +/- 6.6%) were analyzed. LV end-diastolic dimension averaged 58.4 +/- 3.7 mm and was within the generally regarded normal limit (< or =54 mm) in 14.5% of subjects, but was > or =60 mm in 41.1% of subjects. LV septal and posterior wall thicknesses were 10.3 +/- 0.9 and 10.2 +/- 0.9 mm, respectively. Peak E- and A-wave velocities, E/A ratio, LV fractional shortening, and BNP were 96 +/- 16 and 51 +/- 13 cm/s, 2.0 +/- 0.7, 33.5 +/- 4.5%, and 3.1 +/- 3.7 pg/ml, respectively. LV end-diastolic dimension was not correlated with these indexes of LV function or with plasma BNP levels, but was significantly correlated with height, weight, body surface area, fat-free mass, and fat mass. These results show that among very large, highly trained, professional athletes, LV end-diastolic dimension frequently exceeds the traditionally accepted upper limit of normal for the general population. This increase in LV end-diastolic dimension may thus represent an extreme example of the physiologic adaptation of the athlete's heart.

In a study of 32 687 subjects with data on physical activity and body mass index (BMI) collected serially over time, we examined associations with pancreatic cancer mortality (n=212). Despite plausible biologic mechanisms, neither physical activity (multivariate relative risks for increasing levels: 1.00, 0.98, 0.92, and 1.31, respectively) nor BMI (corresponding findings: 1.00, 0.84, 1.08, and 0.99, respectively) significantly predicted pancreatic cancer mortality.

BACKGROUND: Current recommendations prescribe at least moderate-intensity physical activity, requiring >or=3 METs (metabolic equivalents) for >or=30 minutes almost daily, generating approximately 1000 kcal/wk. Defining intensity using an absolute scale in METs may be limited because it neglects variations in physical fitness: an activity requiring a particular MET value commands greater physical effort among less fit than more fit persons. It is unknown whether moderate-intensity exercise, relative to an individual's capacity, is associated with reduced coronary heart disease (CHD) rates. METHODS AND RESULTS: We followed 7337 men (mean age, 66 years) from 1988 to 1995. At baseline, men reported their actual activities and, using the Borg Scale, the perceived level of exertion when exercising (relative intensity). During follow-up, 551 men developed CHD. After multivariate adjustment, the relative risks of CHD among men who perceived their exercise exertion as "moderate," "somewhat strong," and "strong" or more intense were 0.86 (95% confidence interval, 0.66 to 1.13), 0.69 (0.51 to 0.94), and 0.72 (0.52 to 1.00), respectively (P(trend)=0.02), compared with "weak" or less intense. This inverse association extended to men not fulfilling current recommendations, ie, expending <1000 kcal/wk in physical activity or not engaging in activities of >or=3 METs (P(trend)=0.03 and 0.007, respectively). CONCLUSIONS: There is an inverse association between relative intensity of physical activity (an individual's perceived level of exertion) and risk of CHD, even among men not satisfying current activity recommendations. Recommendations for "moderate"-intensity physical activity may need to consider individual fitness levels instead of globally prescribing activities of >or=3 METs.

内分泌代謝(肥満や糖尿病)を専門とする内科医の私は,ボストンのハーバード公衆衛生大学院疫学科,College Alumni Health Studyの研究室に留学中である。当研究室の研究内容,ハーバード公衆衛生大学院の特徴について紹介した。当研究室では,physical activityと健康に関する研究を行っており,私自身の研究テーマは,女性におけるphysical activityと全死亡率の関係である。ハーバード公衆衛生大学院は,1909年に医学部に予防医学・衛生学講座ができたことから始まり,1922年にロックフェラー財団の援助により医学部と隣接して大学院として設立された。私が受講しているコースの必修コースとして,疫学・生物統計学の他に公衆衛生倫理学,環境保健学,健康・社会行動科学のクラスがある。

The aim of this study was to evaluate the effects of pioglitazone on clinical and metabolic parameters, body fat distribution, and serum adiponectin, a recently discovered antiatherosclerotic hormone, in Japanese patients with type 2 diabetes. Ten male patients aged 40 to 66 (57.7 +/- 7.4) years, who were being treated with dietary therapy alone (n = 7) or with a stable dose of sulfonylurea (n = 3), were studied at baseline and after 3 months of pioglitazone treatment (30 mg/d). Body mass index (BMI), blood pressure, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), serum insulin, adiponectin, and lipid profile were measured. Also, visceral adipose tissue area (VAT) and subcutaneous adipose tissue area (SAT) at the umbilical level were determined by computed tomographic (CT) scanning. Mean blood pressure (109 +/- 14 to 101 +/- 10 mm Hg), FPG (8.6 +/- 1.4 to 7.0 +/- 1.0 mmol/L), serum insulin (54 +/- 11 to 30 +/- 8 pmol/L, P <.01 for all), and HbA1c (6.7 +/- 0.8 to 6.1% +/- 0.6%, P =.013) decreased significantly during 3 months of pioglitazone treatment. BMI (26.4 +/- 3.2 to 27.0 +/- 3.5 kg/m2), low-density lipoprotein (LDL) cholesterol (124 +/- 24 to 138 +/- 24 mg/dL) and SAT (155 +/- 69 to 179 +/- 81cm2, P <.05 for all) increased, while triglycerides and high-density lipoprotein (HDL) cholesterol did not change significantly after 3 months of pioglitazone treatment. Serum adiponectin level increased in all patients (4.8 +/- 1.7 to 14.4 +/- 2.1 microg/mL, P =.005). VAT tended to increase (165 +/- 38 to 180 +/- 46 cm2) and VAT/SAT ratio tended to decrease (1.2 +/- 0.3 to 1.1 +/- 0.3), but these differences did not reach statistical significance. These results suggest that pioglitazone exerts good glycemic and blood pressure control despite increased BMI and SAT in Japanese male patients with type 2 diabetes. It is also suggested that pioglitazone may have an antiatherosclerotic effect by increasing serum adiponectin level. Copyright 2002 by W.B. Saunders Company

The action spectra of mating activity among the six species of the Drosophila melanogaster species subgroup were compared to understand how light wavelength affects mating activity. The species fell into three groups with respect to the action spectrum of mating activity. We chose one representative species from each of the three types for detailed study: D. melanogaster, D. sechellia and D. yakuba. The mating activities were investigated under three different light intensities of three monochromatic lights stimulus. Each species showed a unique spectral and intensity response. To know the evolutionary meaning of the light wavelength dependency of mating activity, we superimposed the type of action spectrum of mating activity in these six species on a cladogram. Mating inhibition under UV was conserved in evolution among these species. Furthermore we clarified that D. melanogaster showed low mating activity under UV because males courted less under UV.

A computer assisted literature search was performed (Medline, 1966-2000) to examine the association of physical activity with all cause mortality in women. It was concluded that, by adhering to current guidelines for physical activity and expending about 4200 kJ of energy a week, women can postpone mortality. The magnitude of benefit experienced by women is similar to that seen in men.

1)対象は,幅広いBMI層に分布した.若年者でBMIが高い傾向に,高齢者ではHbA1cが高い傾向にあった. 2)横断的検討で,体脂肪とくに内臓脂肪蓄積が多いほどフィットネス・レベルは低い傾向にあった.体脂肪の多い者でグルコースクランプ法でのインスリン抵抗性が強かった.フィットネス・レベルの高い者ではインスリン抵抗性は弱かった. 3)縦断的検討で,介入後1年の時点で,体脂肪量,体脂肪率,内臓脂肪・皮下脂肪蓄積の減少と共に,フィットネス・レベルは上昇し,HbA1c,空腹時血糖,血糖曲線下面積,総コレステロール,中性脂肪,HDLコレステロール,血圧などの代謝指標は改善した