Nguyen, Tu T.

Jensen, Michael D., Tu T. Nguyen, A. Hernández Mijares, C. Michael Johnson, and Michael J. Murray. Effects of gender on resting leg blood flow: implications for measurement of regional substrate oxidation. J. Appl. Physiol. 84(1): 141–145, 1998.—These studies were designed to examine whether the respiratory quotient (RQ) of leg tissue (primarily skeletal muscle) would increase to a greater degree in women than in men during meal ingestion. We found that mean leg and systemic RQ values were similar in men under both basal and fed conditions, whereas the agreement was poor in women. In women, leg RQ values tended to be greater than the systemic RQ, whereas splanchnic RQ values tended to be lower than the systemic RQ. The possibility that measurement imprecision accounted for the different findings in women could not be excluded because the arteriovenous blood O2 differences were almost twice as great in men as in women (53.7 ± 5.4 vs. 28.6 ± 2.9 ml of O2/l, respectively; P < 0.01), as were venoarterial blood CO2 differences. The smaller arteriovenous differences in women appeared to limit our ability to accurately measure their leg RQ values. O2 uptake relative to leg fat-free mass (FFM) was not different between men and women, whereas leg blood flow relative to leg FFM was greater in women than in men (55 ± 3 vs. 39 ± 2 ml ⋅ kg FFM−1 ⋅ min−1, respectively; P < 0.001). These findings were confirmed by examining data from other studies conducted in our laboratory to create a larger data set. We conclude that resting leg blood flow in women is greater (relative to FFM) than in men, making it more difficult to accurately measure leg RQ in women.

Background Elevated lipoprotein(a) [Lp(a)] levels have been associated with the presence of atherosclerotic disease. However, the results of prospective studies of Lp(a) and cardiovascular disease have been contradictory. Methods and Results From 1968 through 1982, lipoprotein analysis was performed in 11 335 Olmsted County residents. Quantitative cholesterol and triglycerides were obtained along with semiquantitative Lp(a) levels based on electrophoretic pattern. Lp(a) bands were scored from 0 (absent) to 3 (increased). A cohort of 4967 men and 4968 women with no prior history of atherosclerotic disease who had baseline Lp(a) determinations were followed up for 14 years for development of coronary artery disease (CAD) and cerebrovascular disease (CVD). During 131 330 person-years of follow-up, there were 1848 CAD events and 841 CVD events. Age, diabetes, hypertension, cholesterol, and triglycerides were significantly and independently associated with an increased risk of CAD and CVD in men and women. There was a significant increase in the adjusted hazards ratio for CAD with increasing Lp(a) levels for men and women. For Lp(a) level 3, the hazard ratio was 1.9 (range, 1.3 to 2.9) in women and 1.6 (range, 1.0 to 2.5) in men. The adjusted hazard ratio for CVD showed an irregular association with Lp(a) levels in men and no association in women. Conclusions In this cohort of 9936 men and women initially free of cardiovascular disease who were followed up for 14 years, Lp(a) was a significant predictor of risk of future CAD. Lp(a) was a weak risk factor for CVD in men and was not a significant predictor of CVD risk in women.

Abstract Bone mass is purportedly reduced by an endogenous or exogenous excess of thyroid hormone or, perhaps, by calcitonin deficiency. Patients who have undergone thyroidectomy could be subject to all of these effects, yet their practical implications in terms of fracture risk are poorly defined. Interpretation is further hampered by the focus on women, where results may be influenced by involutional osteoporosis. Consequently, we assessed the potential for fractures among the 136 Rochester, Minnesota men who underwent thyroidectomy between 1935 and 1979, relative to a group of age-matched control men from the community. With 2194 person-years of follow-up in each group, survival free of any fracture of vertebra, proximal humerus, distal forearm, pelvis, or proximal femur was similar in the two groups (p = 0.23), and the relative risk of any of these fractures for thyroidectomized patients versus their controls was increased only 1.5-fold (95% CI, 0.7–3.2). The difference was entirely accounted for by a statistically significant excess of proximal femur fractures in the men with thyroidectomy. Risk factors for fractures among men with thyroidectomy included greater age at surgery, greater extent of surgery, and the presence of risk factors for secondary osteoporosis. Thus, thyroidectomy, performed mainly for adenoma or goiter, seems to have little overall influence on the risk of age-related fractures in men. However, the association with hip fractures requires further evaluation.