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Biomedical subjects

C Gilligan

Publications and source records attributed to C Gilligan.

13 recordsLinked to original sources
PubMed1991

Physical activity effects on bone metabolism.

The incidence of osteoporotic fractures rises exponentially with age and is increasing faster than the demographic increase in the aging population. Physical activity has great potential to reduce the risk for osteoporotic fractures. Three independent but interactive factors contribute to the risk of fractures: bone strength, the risk of falling, and the effectiveness of neuromuscular response that protects the skeleton from injury. Exercise can reduce fracture risk not only by preventing bone loss, but by decreasing the risk of falling and the force of impact by improving strength, flexibility, balance, and reaction time. Extreme inactivity causes rapid bone loss of up to 40%, while athletic activity results in bone hypertrophy of up to 40%. Exercise intervention programs have reduced bone loss or increased bone mass in both men and women of various ages and initial bone status. These benefits have been shown for arm bone mineral content, total body calcium, spine, calcium bone index, tibia, and calcaneus. In both middle-aged and elderly women, physical activity intervention reduced bone loss or increased bone mass. The mechanisms for maintenance of skeletal integrity rely on a cellular response to hormonal and mechanical load stimuli. Studies in animal models show that training affects cellular activity. In osteoporotics, cellular erosion is increased and mineral apposition rate (MAR) decreased compared with normal age-matched controls. In contrast to this, sows trained on a treadmill 20 min per day for 20 weeks had greater active periosteal surface, periosteal MAR, and osteonal MAR than untrained sows.

Adolescent↗
PubMed1991

Muscular strength and bone density with weight training in middle-aged women.

Previous research has demonstrated positive correlations between bone mass and both physical activity and muscular strength. There is a paucity of information describing the specific type of exercise which most benefits the human skeleton. The effects of a 1 yr weight training program on 18 middle-aged women participating in an endurance dance program (E + W) compared with 17 other women in the endurance dance program only (E) and with 19 sedentary controls (C) were studied by measuring muscular strength and bone mineral density (BMD). Eighteen women in the E + W group demonstrated increases in all strength measurements, whereas the E and C groups either had smaller increases or had declined. A significant group x test interaction term, indicating that groups responded differently over time, was observed for nondominant isokinetic elbow flexion measured through the range of motion at a constant velocity of 60 degrees.s-1 (P less than 0.05), nondominant isokinetic elbow extension at 180 degrees.s-1 (P less than 0.01), and nondominant isokinetic elbow flexion at 180 degrees.s-1 (P less than 0.05). BMD did not change significantly except that a significant group x test interaction term appeared for the radius ultradistal site (P less than 0.01). BMD of the humerus and femoral Ward's triangle increased nonsignificantly in both E and E + W over the year. This weight training program increased muscular strength but did not increase measured bone mass.

Adult↗
PubMed1989

Deterring bone loss by exercise intervention in premenopausal and postmenopausal women.

This study investigated the efficacy of 4 years of exercise intervention in deterring bone loss in middle-aged women, and is a correction and extension of previously published data. Sixty-two control subjects (mean age 50.8) and 80 exercise subjects (mean age 50.1) completed a 4-year study. Subjects exercised three times a week, 45 minutes per session. Bilateral radius, ulna, and humerus bone mineral content (BMC) and width (W) were measured on each subject 11 times over the 4-year period. The two groups did not differ initially in age, height, or weight, but the control group had a greater maximum VO2 (ml/kg/min) than the exercise group. Slopes and intercepts of the bone variables vs. time were determined for each subject, and these values were used for between-group comparisons of loss. The control group BMC and BMC/W declined significantly in all three bones in both arms. The exercise group rate of decline was significantly less than that of the control group for 12 of the 18 bone variables. The greatest effect of the exercise intervention was on the ulna and radius. Exercise subjects lost significantly less than control subjects in left and right ulna and radius BMC and BMC/W, and left ulna and radius W. Lesser differences between groups were observed in the humerus. BMC and W loss rates of the left humerus were reduced in the exercise group, with no difference between exercise and control subjects in the other humerus variables. To determine if menopausal status influenced the response to exercise, we analyzed the difference between groups for premenopausal and postmenopausal subjects separately. Regardless of menopausal status, exercise subjects had lower bone loss rates than control subjects. In both premenopausal and postmenopausal subjects, exercise reduced bone loss significantly for 10 of the 18 bone variables. It can be concluded that physical activity significantly reduces bone loss in the arms of middle-aged women.

Adult↗
PubMed1989

Calcium supplementation and bone loss in middle-aged women.

This 4-y study investigated the effects of a calcium carbonate supplement on bone loss in 169 women aged 35-65 y, randomly assigned to placebo and treatment (1500 mg Ca/d) groups in a double-blind design. Bone mineral content (BMC) and width (W) were measured bilaterally on the radius, ulna, and humerus. BMC and BMC/W loss rates were consistently lower in treatment than in control subjects. Loss was significantly reduced in the left and right humerus and the right radius. In premenopausal subjects, only left humerus BMC loss was significantly reduced by Ca supplementation. In postmenopausal treatment subjects, BMC and BMC/W bone loss was reduced in all 12 (bilateral radius, ulna, and humerus) of the bone variables measured, 5 at p less than 0.01 and 2 at p less than 0.05. Ca supplementation counteracted a large portion of the additional bone loss attributable to menopause in this population.

Absorptiometry, Photon↗
PubMed1985

Effects of intraindividual and interindividual variation in repeated dietary records.

In this study 5,115 daily diet records were collected from 151 women on two randomly selected days per sampling month (29 days) over a two-year period. Yearly estimates of the ratios of intraindividual (sigma w2) and interindividual (sigma b2) variance components were calculated for dietary intake of 15 nutrients and for dietary intake + vitamin/mineral supplements. From one year to the next, corresponding ratios of sigma w2/sigma b2 were nearly identical. Intraindividual variation in dietary intake of all 15 nutrients was greater than interindividual variation (sigma w2/sigma b2 greater than 1). Variance component ratios for highly supplemented nutrients such as iron, vitamin C and B vitamins were less than one (sigma w2/sigma b2 less than 1). Using the ratios of sigma w2/sigma b2, it was calculated that between six and 99 repeated records measuring dietary intake and between two and 31 records measuring total intake may be needed per individual to ensure that the estimate of the population correlation (rho DF) between an individual's "usual" dietary intake or total intake of a dietary risk factor and an individual's mean or usual level of a physiologic risk factor was within 10% of the true population correlation coefficient (rho xy). It was also found that twice as many dietary records per individual were required to estimate the population slope (beta xy) within 10%. These results have serious implications for the design and analysis of prospective nutritional studies.

Adult↗
PubMed1984

A two-year dietary survey of middle-aged women: repeated dietary records as a measure of usual intake.

A two-year survey of the dietary consumption and supplement use patterns of adult women was conducted at the University of Wisconsin-Madison. Participants were asked to record their diet on two randomly selected days per month over a two-year period. Each subject filled out an average of 19 records a year, for an overall 71% return rate. Because of the sampling design, it was possible to estimate each woman's "usual" or average daily dietary and total intake (diet plus supplements) of 15 nutrients. Many women were consuming usual amounts of energy, calcium, iron, magnesium, vitamin B-6, and, especially, zinc and total folate that were 30% to 50% below recommended levels. It was also found that the women generally took vitamin/mineral supplements for nutrients already adequately supplied in the diet. Low nutrient intakes may have been due, in part, to underreporting of food intakes.

Adult↗
PubMed1982

New maps of development: new visions of maturity.

Two modes of moral reasoning are distinguished in boys' and girls' discussions of moral dilemmas: one oriented to justice and rights, one to care and response. These different modes are associated with different forms of self-definition and reflect different images of relationships. The contrasting images of hierarchy and web derive from childhood experiences of inequality and interdependence which give rise to the ideals of justice and of care. The representation of these two lines of development and their interplay yields a new mapping of human growth.

Child↗
PubMedDate not supplied

Sex differences and interpersonal relationships: a cross-sectional sample in the U.S. and India.

This study introduces a methodology for exploring sex differences and life span patterns in a small sample for the purpose of generating hypotheses concerning the frequency and kinds of relationships people identify as important. Sixty-two participants from the United States and India, ranging in age from nineteen to seventy-five were interviewed as part of a study on ego and moral development. These open-ended, semistructured interviews yielded information on relationships that was subsequently coded for analysis. Sex differences were found in the number of relationships mentioned, with females mentioning a higher number of relationships than males. Life span patterns regarding the number of relationships mentioned were different for men and women between ages nineteen to thirty-one, with women naming more relationships. At age thirty-five there was a convergence in the number of relationships mentioned by both sexes. This age also was the low point in the number of relationships mentioned by both sexes, with later life ages.

Adult↗