The effect of inflammation on serum zinc concentrations and the prevalence estimates of population-level zinc status among Congolese children aged 6-59 months

BACKGROUND/OBJECTIVES

Zinc is a negative acute-phase reactant; hence, its concentration decreases in the presence of inflammation. There is no current consensus on how to control for the effect of inflammation on serum zinc, which has implications for accurate estimates of population-level zinc status. We aimed to measure the association between inflammation and serum zinc concentrations and to compare the means and the prevalence of zinc deficiency using unadjusted and inflammation-adjusted serum zinc concentrations among Congolese children.

SUBJECTS/METHODS

Non-fasting blood was collected in the afternoon in trace element-free vacutainers from 744 apparently healthy children aged 6-59 months in the Democratic Republic of the Congo. Serum was analyzed for zinc, C-reactive protein (CRP) and α-1 acid glycoprotein (AGP) for 665 children with complete data for all three biomarkers. Linear regression was used to generate correction factors (CFs) based on three stages of inflammation: incubation (CRP >5 mg/l and normal AGP), early convalescence (CRP >5 mg/l and AGP >1 g/l) and late convalescence (AGP >1 g/l and normal CRP), relative to no inflammation.

RESULTS

Overall unadjusted mean±s.d. serum zinc concentration was 9.4±2.1 μmol/l. Study-generated CFs (95% confidence interval) for incubation, early and late convalescence were 1.01 (0.88, 1.14), 1.15 (1.11, 1.21) and 1.07 (1.03, 1.11), respectively. After applying the CFs, overall adjusted mean±s.d. serum zinc concentration was 10.1±2.2 μmol/l, and prevalence of zinc deficiency (<8.7 μmol/l) decreased from 35% (n=234/665) to 24% (n=160/665).

CONCLUSIONS

Adjustment of zinc concentrations for inflammation is warranted when assessing population-level zinc status.European Journal of Clinical Nutrition advance online publication, 23 August 2017; doi:10.1038/ejcn.2017.127.

Lunch-time food source is associated with school hour and school day diet quality among Canadian children

BACKGROUND

There is limited research on the dietary behaviours of Canadian children at school, including where students obtain food from during school hours or whether lunch-time food source influences diet quality.

METHODS

Nationally representative cross-sectional data from 24-h dietary recalls were analysed from the 2004 Canadian Community Health Survey (n = 4589). Dietary outcomes included school hour and school day dietary intakes and School Healthy Eating Index (S-HEI) scores. Survey-weighted covariate-adjusted linear regression models examined differences in dietary outcomes across lunch-time food source groups.

RESULTS

The majority of children (72.8%) reported bringing lunch from home, whereas fewer students obtained lunch from off-campus locations (11.6%), schools (9.6%) or skipped lunch (5.9%). Compared to off-campus lunches, home-packed lunches were significantly higher in fibre, vitamins A, D and C, thiamin, magnesium, iron, grains, vegetables and fruit, but lower in total calories, fat and calories from minimally nutritious foods. Average school hour diet quality required improvement for all age groups, although S-HEI scores did not differ significantly by lunch-time food source among 6-8-year-old children. However, for children age 9-17 years, bringing a home-packed lunch was associated with significantly higher S-HEI scores compared to students obtaining lunch from off-campus locations. After adjusting for age and sex, lunch-time food source was also significantly associated with whole day dietary quality.

CONCLUSIONS

Although the nutritional quality of off-campus lunches was lower than home-packed lunches, the quality of foods was suboptimal, regardless of food source. Strategies are needed to enhance access to nutritious foods on campus and improve the nutritional quality of packed lunches, which supply the majority of lunch-time foods consumed by Canadian children.

Associations of Protein Intake and Protein Source with Bone Mineral Density and Fracture Risk: A Population-Based Cohort Study

High dietary protein has been hypothesized to cause lower bone mineral density (BMD) and greater fracture risk. Previous results are conflicting and few studies have assessed potential differences related to differing protein sources.

OBJECTIVE

To determine associations between total protein intake, and protein intake by source (dairy, non-dairy animal, plant) with BMD, BMD change, and incident osteoporotic fracture.

DESIGN/SETTING

Prospective cohort study (Canadian Multicentre Osteoporosis Study). Participants/Measures: Protein intake was assessed as percent of total energy intake (TEI) at Year 2 (1997-99) using a food frequency questionnaire (N=6510). Participants were contacted annually to ascertain incident fracture. Total hip and lumbar spine BMD was measured at baseline and Year 5. Analyses were stratified by group (men 25-49 y, men 50+ y, premenopausal women 25-49 y, and postmenopausal women 50+ y) and adjusted for major confounders. Fracture analyses were limited to those 50+ y.

RESULTS

Intakes of dairy protein (with adjustment for BMI) were positively associated with total hip BMD among men and women aged 50+ y, and in men aged 25-49. Among adults aged 50+ y, those with protein intakes of <12% TEI (women) and <11% TEI (men) had increased fracture risk compared to those with intakes of 15% TEI. Fracture risk did not significantly change as intake increased above 15% TEI, and was not significantly associated with protein source.

CONCLUSIONS

In contrast to hypothesized risk of high protein, we found that for adults 50+ y, low protein intake (below 15% TEI) may lead to increased fracture risk. Source of protein was a determinant of BMD, but not fracture risk.

Longitudinal changes in calcium and vitamin D intakes and relationship to bone mineral density in a prospective population-based study: the Canadian Multicentre Osteoporosis Study (CaMos)

OBJECTIVES

Our objective was to study changes in calcium and vitamin D intakes over time, and their cross-sectional and longitudinal associations with bone mineral density (BMD).

METHODS

We followed 9382 women and men aged ≥25 and 899 aged 16-24, for 10 and 2 years respectively.

RESULTS

Calcium and vitamin D intakes increased over time in adults, but decreased in women aged 16-18. The increased intakes in adults were largely attributable to the increased use of calcium and/or vitamin D supplements. Both the percentage of supplement users and average dose among users increased over time. There was nevertheless a high prevalence of calcium and vitamin D intake below the estimated average requirement. At baseline, higher calcium and vitamin D intakes were associated with higher total hip and femoral neck BMD in young men, and cumulatively high levels of calcium and vitamin D intakes over time contributed to better BMD maintenance at lumbar spine and hip sites in adult women.

CONCLUSIONS

Although total intakes, particularly of vitamin D, frequently fell below the Institute of Medicine recommendations despite an increase over time in supplement use, we found some positive associations between total calcium and vitamin D intake and bone health.

Healthy midlife Canadian women: how bone health is considered in their food choice systems

BACKGROUND

The incidence of osteoporosis is predicted to increase as Western populations age. Diet is considered to be an important modifiable factor in bone health, yet the diets of many women are insufficient in calcium and vitamin D, which comprise two key nutrients for bone health. This focus group study explored ways in which midlife women consider bone health in their personal food choice systems.

METHODS

Data were obtained in six audio-recorded focus groups from a total of 36 women from upper, middle and lower income neighbourhoods. Open and axial coding and thematic analysis revealed shared and unique themes across and within the income groups. Use of member checks, peer debriefing, and independent and team data analysis enhanced rigour in the findings.

RESULTS

All participants were aware of osteoporosis. Most women idealised making simple food decisions and eating for 'holistic' health, but not specifically for bone health. Most midlife women were not motivated to change their diets, few had deliberately increased their intake of calcium and vitamin D through foods and supplements, and few others had simplified their food decisions.

CONCLUSIONS

Midlife women in the present study did not make eating for bone health a priority in their food choice systems. Instead, women wanted to eat for 'holistic' health, and only by implication bone health.

Energy recommendations for normal weight, overweight and obese children and adolescents: are different equations necessary?

In 2002/2005, separate energy requirement equations were generated by the Institute of Medicine's (IOM) Dietary Reference Intake process for normal weight and overweight/obese children and adolescents. The current paper questions the theoretical rationale of having two sets of equations (based solely on body-weight classification): when body weight is considered, overweight and obese children and adolescents do not seem to differ from their normal weight counterparts in energy expended for basal metabolism or physical activity tasks. However, energy needs for weight maintenance among overweight/obese girls were consistently higher when predicted using the equations for overweight/obese individuals compared with those developed for normal weight individuals. In contrast, among overweight/obese boys, they were consistently lower. Although the differences are within the variability of the estimates, even theoretical support for a higher energy intake (as occurs in girls) seems unwise because of the potential contribution to a higher body mass in children who are already at risk. It is the opinion of the authors that the IOM revisit the use of two separate equations and generate one set that is appropriate for all children and adolescents.

Self-reported lifetime physical activity and areal bone mineral density in healthy postmenopausal women: the importance of teenage activity

Girls who exercise athletically have higher bone mass than their sedentary counterparts, and this difference may be sustained in adulthood. However, whether moderate physical activity during youth confers lasting benefits for bone is unclear. We explored lifetime physical activity and current areal bone mineral density (aBMD) in 78 postmenopausal women with no known history of osteoporosis. Subjects reported physical activity for four age periods (12-18, 19-34, 35-49, > or = 50 years) using the Historical Leisure Activity Questionnaire, completed two 3-day food records, had measurements of height and weight, and aBMD assessed using dual-energy X-ray absorptiometry at the lumbar spine (L1-4) and proximal femora. Low aBMD was detected at the lumbar spine in 43 (56%) women and at the proximal femora in 38 (49%) women. Teenage physical activity, but not activity during other age periods, was associated with current aBMD at both sites (lumbar spine r = 0.31, P < 0.01; mean proximal femora r = 0.33, P < 0.01). Weight-bearing physical activity (WBPA) at age 12-18 years was the only predictor of current lumbar spine aBMD (R (2) = 0.110, P = 0.004). Current proximal femoral aBMD was positively predicted by physical activity at age 12-18 years and negatively predicted by current age (R (2) = 0.175, P = 0.001). Subjects above the median of teen WBPA had 5-8% higher current aBMD than those reporting less teen WBPA and were less likely to be classified with osteopenia or osteoporosis. Moderate physical activity during years of peak bone acquisition appears to have lasting benefits for lumbar spine and proximal femoral aBMD in postmenopausal women.

Canadian dietitians' views and practices regarding obesity and weight management

OBJECTIVE

To provide insight into Canadian dietitians' attitudes and practices regarding obesity and weight management.

DESIGN

Cross-sectional mail survey of a stratified random sample of members of Canadian dietetic associations.

SUBJECTS

A total of 514 dietitians (74% of those surveyed), 350 (69%) of whom actively counselled overweight/obese clients.

MEASUREMENTS

Participants received a questionnaire to assess dietitians' attitudes regarding obesity and overweight, views regarding their role in weight management, counselling practices, and the criteria used to judge success. Demographic variables were collected.

RESULTS

Most dietitians believed that obesity contributes to morbidity and mortality, and that small weight losses produced important health benefits. However, 80% agreed that health indicators other than weight loss should be the focus of obesity management, and 55% specifically recommended that clients not weigh themselves. Instead, weight management was promoted by recommending healthy eating and increased physical activity. Three-quarters agreed that they are the profession best trained to manage obesity but two-thirds believed their time would be better spent preventing rather than managing obesity. Dietitians most valued education received from on-the-job support and mentoring from other dietitians. Participants reported wanting to learn more about motivational and behavioural modification counselling techniques.

CONCLUSIONS

Canadian dietitians follow a lifestyle approach to weight management. Studies are required to formally assess the effectiveness of various aspects of this approach.

Nutrition and physical activity--why we must move from a casual acquaintance to a lifelong partnership. 2001 Ryley-Jeffs memorial lecture

Both nutrition and physical activity have important roles in health promotion and disease prevention, and are viewed by the public as closely related and synergistic. However, the present level of interaction between professionals in the two areas is limited, and could be described as a "casual acquaintance." Using heart disease, osteoporosis and obesity as examples of chronic conditions that affect the health and well-being of Canadians, reasons why the level of interaction between nutrition and exercise professionals must move to a "lifelong partnership" are discussed. For each, evidence for the roles of nutrition and physical activity in prevention and management is presented, along with data to support the concept that attention to both factors is likely to be more beneficial than attention to either alone. Obesity is presented as a risk factor for inactivity rather than a chronic disease per se: when fitness level is controlled, data suggest that lean and obese men have similar mortality rates. However, the prevalence of low fitness is much higher among obese individuals. Moving from a casual acquaintance to a lifelong partnership will require modification of the education of nutrition and fitness professionals, as well as a personal commitment by members of both groups.

Dietary restraint, exercise, and bone density in young women: are they related?

PURPOSE

Women with high scores for dietary restraint have been found to have higher 24-h urinary cortisol excretion and a higher prevalence of subclinical ovulatory disturbances, both of which may be risk factors for bone loss. The purpose of this study was to explore relationships between dietary restraint and bone health in regularly menstruating young women.

METHODS

62 women (age: 21.7 +/- 2.5 yr) had body composition and total body and lumbar spine bone mineral density (BMD) and content (BMC) assessed using dual-energy x-ray absorptiometry. Dietary restraint was assessed using the restraint subscale from the Three-Factor Eating Questionnaire: 29 women had low restraint (LR; restraint score 0--5), 33 had high restraint (HR; restraint score 13--21). Exercise (h x wk(-1)) was assessed by questionnaire on two occasions.

RESULTS

LR and HR women were similar in age and body composition (fat mass = 15.0 +/- 4.7 kg, lean mass = 40.9 +/- 4.9 kg), but HR women exercised more (3.4 +/- 1.7 vs 2.2 +/- 1.8 h x wk(-1), P < 0.05). Exercise was correlated with BMD and BMC, and when it was included as a covariate, total body BMC was significantly lower in HR than LR women. In multiple regression analysis, weekly hours of exercise and restraint score were significant predictors of total body BMD and BMC.

CONCLUSION

The observations of this cross-sectional study suggest that high levels of cognitive dietary restraint, or associated factors such as higher cortisol, may attenuate the positive effects of exercise on bone in young women.

Eating attitudes and habitual calcium intake in peripubertal girls are associated with initial bone mineral content and its change over 2 years

This 2-year prospective study examined associations among bone mineral acquisition and physical, maturational, and lifestyle variables during the pubertal transition in healthy girls. Forty-five girls, initially 10.5+/-0.6 years, participated. Body composition and bone mineral content (BMC) at the spine and total body (TB) were assessed at baseline and annually thereafter using dual-energy X-ray absorptiometry (DXA). Nutrient intakes were assessed using 3-day diet records and a calcium food frequency questionnaire (FFQ), physical activity by questionnaire, sexual maturation using Tanner's stages of breast and pubic hair maturation, growth by height and weight, and eating attitudes using the children's Eating Attitudes Test (Children's EAT). Mean children's EAT subscale scores (dieting, oral control [OC], and bulimia) were stable over time. Median split of OC subscale scores was used to form high and low OC groups. Groups had similar body composition, dietary intake, activity, and Tanner stage at baseline and 2 years. Using height, weight, and Tanner breast stage as covariates, girls with low OC scores had greater TB BMC at baseline (1452+/-221 g vs. 1387+/-197 g; p = 0.030) and 2 years (2003+/-323 g vs. 1909+/-299 g; p = 0.049) and greater lumbar spine (LS) BMC at 2 years (45.2+/-8.8 g vs. 41.2+/-9.6 g; p = 0.042). In multiple regression analysis, OC score predicted baseline, 2 years, and 2-year change in TB and spinal BMC, contributing 0.9-7.6% to explained variance. Calcium intake predicted baseline, 2 years, and 2-year change in TB BMC, explaining 1.6-5.3% of variance. We conclude that both OC and habitual calcium intake may influence bone mineral acquisition.

Cognitive dietary restraint is associated with higher urinary cortisol excretion in healthy premenopausal women

BACKGROUND

Cognitive dietary restraint, assessed by the Three-Factor Eating Questionnaire restraint subscale, is associated with subclinical menstrual cycle disturbances. This association may be mediated by stress-activated cortisol release.

OBJECTIVE

We assessed whether 24-h urinary cortisol excretion differs between women with high and low restraint scores.

DESIGN

Participants (aged 21.6+/-2.5 y; n = 62) with normal-length menstrual cycles and high (n = 33) or low (n = 29) restraint scores completed a questionnaire describing weight history, dietary practices, and exercise. Cortisol, calcium, and creatinine were measured in urine collected over 24 h on a day when all food and beverages were provided and measured. Previously, 3-d food records and anthropometric measurements were obtained.

RESULTS

Age, height, weight, body mass index, and length of menstrual cycle were similar between groups. The reported amount of exercise was higher (3.4+/-1.7 compared with 2.2+/-1.8 h/wk; P<0.05) and energy intakes (assessed from 3-d and 24-h food records) were lower in the high- than in the low-restraint group. Ratios of urinary cortisol (nmol) to creatinine (mmol) were higher in the high-restraint than in the low-restraint group (42.9+/-12.9 compared with 36.3+/-8.9; P<0.05), whereas ratios of urinary calcium (mmol) to creatinine were lower (0.3+/-0.1 compared with 0.4+/-0.2; P<0.05) in the high-restraint group. Urinary cortisol was not associated with exercise, nutrient intakes, or anthropometric measurements.

CONCLUSIONS

High dietary restraint scores are associated with urinary cortisol, a biological marker of stress, and high cortisol excretion may affect bone health. Our results suggest that further research is warranted to clarify these associations and to determine whether they persist over time.

Relative weight, weight loss efforts and nutrient intakes among health-conscious vegetarian, past vegetarian and nonvegetarian women ages 18 to 50

OBJECTIVE

To compare relative weight, weight loss efforts and nutrient intakes among similarly health-conscious vegetarian, past vegetarian and nonvegetarian premenopausal women.

METHODS

Demographic data, lifestyle practices and weight loss efforts (by questionnaire), body mass index (BMI;kg/m2) and dietary intake (via multiple-pass 24-hour diet recall) were compared in a convenience sample of 90 current vegetarians, 35 past vegetarians and 68 nonvegetarians.

RESULTS

Age (31.9 +/- 8.8), educational attainment, smoking status, alcohol use, physical activity and perceived health status were similar among the three groups of women. BMI did not differ by dietary pattern and averaged 23.7 +/- 4.7 for all women combined. Participants had intentionally lost > or = 10 pounds a mean of 2.1 times, and 39% of women perceived themselves to be overweight; again, no differences were observed among dietary groups. Dietary intakes of vegetarians and current nonvegetarians were consistent with current recommendations for macronutrient composition (< 30% fat, < 10% saturates). Compared to current nonvegetarians, current vegetarians had lower intakes of protein, saturated fat, cholesterol, niacin, vitamins B12 and D, and higher fiber and magnesium intakes. Vegetarians' mean vitamin B12 and D intakes were well below recommendations.

CONCLUSIONS

Relative weight and weight loss efforts do not differ by dietary pattern among similarly health-conscious vegetarian and nonvegetarian women. The only differences in nutrient intake with potential health implications were vitamins D and B12.

Effects of increased consumption of fluid milk on energy and nutrient intake, body weight, and cardiovascular risk factors in healthy older adults

OBJECTIVE

To assess the impact of increased consumption of milk, without other dietary advice, on older adults' energy and nutrient intakes, weight, cardiovascular risk factors (blood pressure, plasma lipid levels), and quality of life.

SUBJECTS/SETTING

Two hundred four healthy men and women, aged 55 to 85 years, who consumed fewer than 1.5 dairy servings per day were chosen from six US academic health centers.

DESIGN

Randomized, controlled open trial.

INTERVENTION

Advice to increase skim or 1% milk intake by 3 cups per day (n = 101) or to maintain usual diet (n = 103) for 12 weeks after a 4-week baseline period.

MAIN OUTCOME MEASURES

Changes in energy and nutrient intake assessed from 3-day food records, body weight, blood pressure, and plasma lipid levels.

STATISTICAL ANALYSES PERFORMED

Group-by-time analysis of variance with repeated-measures, chi 2 test.

RESULTS

Compliance with the intervention was good. Compared with controls, participants in the milk-supplemented group significantly increased energy, protein, cholesterol, vitamins A, D, and B-12, riboflavin, pantothenate, calcium, phosphorus, magnesium, zinc, and potassium intakes. Prevalence of nutrient inadequacy, assessed for nutrients with Estimated Average Requirements, decreased among women in the milk group for magnesium (40% at baseline vs 13% at 12 weeks, P < .001) and vitamin B-12 (6% vs 0%, P < .05) and tended to decrease (P < .10) for protein and thiamin (women) and magnesium and vitamin B-6 (men). The milk group gained 0.6 kg more than control group (P < .01); however, weight gain was less than predicted, which suggests some compensation for the added energy from milk. Blood pressure decreased similarly over time in both groups. Total and low-density lipoprotein cholesterol levels, and the ratio of total cholesterol to high-density lipoprotein cholesterol, were unchanged. Triglyceride levels increased within the normal range in the milk group (P = .002). Quality of life scores were high at baseline and remained high throughout.

APPLICATIONS/CONCLUSIONS

Older adults can successfully increase milk intake, thereby meaningfully improving their nutrient intakes. Dietitians can play a key role in disseminating this advice.

Augmented trochanteric bone mineral density after modified physical education classes: a randomized school-based exercise intervention study in prepubescent and early pubescent children

BACKGROUND

Of the few exercise intervention studies focusing on pediatric populations, none have confined the intervention to the scheduled physical education curriculum.

OBJECTIVE

To examine the effect of an 8-month school-based jumping program on the change in areal bone mineral density (aBMD), in grams per square centimeter, of healthy third- and fourth-grade children.

STUDY DESIGN

Ten elementary schools were randomized to exercise (n = 63) and control groups (n = 81). Exercise groups did 10 tuck jumps 3 times weekly and incorporated jumping, hopping, and skipping into twice weekly physical education classes. Control groups did regular physical education classes. At baseline and after 8 months of intervention, we measured aBMD and lean and fat mass by dual-energy x-ray absorptiometry (Hologic QDR-4500). Calcium intake, physical activity, and maturity were estimated by questionnaire.

RESULTS

The exercise group showed significantly greater change in femoral trochanteric aBMD (4.4% vs 3.2%; P <.05). There were no group differences at other sites. Results were similar after controlling for covariates (baseline aBMD change in height, change in lean, calcium, physical activity, sex, and ethnicity) in hierarchical regression.

CONCLUSIONS

An easily implemented school-based jumping intervention augments aBMD at the trochanteric region in the prepubertal and early pubertal skeleton.

Dietary changes favorably affect bone remodeling in older adults

OBJECTIVE

To determine whether dietary counseling to increase milk intake could produce useful changes in the calcium economy and what, if any, other nutrition-related changes might be produced.

DESIGN

Randomized, open trial.

SUBJECTS/SETTING

Two hundred four healthy men and women, aged 55 to 85 years, who habitually consumed fewer than 1.5 servings of dairy foods per day. Six academic health centers in the United States.

INTERVENTION

Subjects were instructed to consume 3 servings per day of nonfat milk or 1% milk as a part of their daily diets, or to maintain their usual diets, for a 12-week intervention period, which followed 4 weeks of baseline observations.

MAIN OUTCOME MEASURES

Energy and nutrient intake assessed from milk intake logs and 3-day food records; serum calciotrophic hormone levels at baseline and at 8 and 12 weeks; urinary excretion of calcium and N-telopeptide at 12 weeks.

STATISTICAL ANALYSES

Repeated-measures analysis of variance.

RESULTS

In the milk-supplemented group, calcium intake increased by 729 +/- 45 mg/day (mean +/- standard error), serum parathyroid hormone level decreased by approximately 9%, and urinary excretion of N-telopeptide, a bone resorption marker, decreased by 13%. Urine calcium excretion increased in milk-supplemented subjects by 21 +/- 7.6 mg/day (mean +/- standard error), less than half the amount predicted to be absorbed from the increment in calcium intake. All of these changes were significantly different from baseline values in the milk group and from the corresponding changes in the control group. Bone-specific alkaline phosphatase level (a bone formation marker) fell by approximately 9% in both groups. Serum level of insulin-like growth factor-1 (IGF-1) rose by 10% in the milk group (P < .001), and the level of insulin-like growth factor binding protein-4 (IGFBP-4) fell slightly (1.9%) in the milk group and rose significantly (7.9%) in the control group (P < .05).

APPLICATIONS/CONCLUSIONS

The changes observed in the calcium economy through consumption of food sources of calcium are similar in kind and extent to those reported previously for calcium supplement tablets. The increase in IGF-1 level and the decrease in IBFBP-4 level are new observations that are beneficial for bone health. Important improvements in skeletal metabolism can feasibly occur in older adults by consumption of food sources of calcium. Dietitians can be confident that food works, and that desired calcium intakes can be achieved using food sources.

Energy balance in women with breast cancer during adjuvant treatment

OBJECTIVE

To compare weight, body composition, and major determinants of energy balance of women treated with adjuvant chemotherapy (n = 8) using Adriamycin and cyclophosphamide (AC), or radiation therapy (n = 10).

DESIGN

The study used a nonrandomized prospective design. Pretreatment and posttreatment measurements, obtained at baseline and 12 weeks, respectively, included weight, body composition (determined using dual-energy x-ray absorptiometry), energy intake (determined using 3-day food records), resting energy expenditure (determined in indirect calorimetry), and physical activity (determined using 3-day physical activity records). Poststudy follow-up weights were obtained for 13 women.

SUBJECTS/SETTING

Eighteen premenopausal women with breast cancer in the early stage, recruited from outpatient clinics, participated in and completed the study.

STATISTICAL ANALYSES PERFORMED

Unpaired Student t tests or X2 tests were used to test for differences in baseline subject characteristics, and repeated measures analysis of variance was used to compare groups before and after treatment.

RESULTS

Body weight was unchanged in both treatment groups during the study, although poststudy follow-up weights (n = 13) suggested a tendency for weight gain in both groups. Significant changes in body composition for both groups included a mean loss of 0.8 kg total lean body mass (LBM), a mean loss of 0.4 kg LBM in the leg region, and a mean 1.3% increase in percent body fat, from 40.0% to 41.3%. Overall, no between-group differences were observed in any factors associated with energy balance.

APPLICATIONS

In this short-term study, AC chemotherapy using fewer antineoplastic agents and number of treatments than most chemotherapy protocols for breast cancer, did not result in weight gain during treatment. Regardless of weight gain, changes in body composition may occur in women with breast cancer during or after treatment. These potential changes have important implications for preventive nutrition counseling.

Vegetarianism and menstrual cycle disturbances: is there an association?

The question of whether menstrual disturbances are more common in vegetarian than in nonvegetarian women is complex. Disturbances of the cycle may be clinical (ie, amenorrhea or oligomenorrhea) or subclinical (i.e., normal-length cycles with anovulation or a short or defective luteal phase). Detection of the latter requires that the menstrual cycle be monitored, but may help prevent recruitment bias in studies comparing vegetarians with nonvegetarians because vegetarians with menstrual disturbances may be more likely to volunteer for a study on menstrual disturbances and vegetarianism. Three general mechanisms that could contribute to menstrual disturbances that may differ between vegetarians and nonvegetarians include energy imbalances associated with body-weight disturbances or exercise, psychosocial and cognitive factors, and dietary components. Evidence for each of these mechanisms is reviewed and studies comparing menstrual function between vegetarians and nonvegetarians are described in this article. Although results from several cross-sectional studies suggest that clinical menstrual disturbances may be more common in vegetarians, a prospective study that controlled for many potential confounders found that subclinical disturbances were less common in weight-stable, healthy vegetarian women. Because the sample studied may not be representative of all vegetarian women, however, these results cannot be generalized. Population studies are needed to draw definitive conclusions.

Running and ovulation positively change cancellous bone in premenopausal women

PURPOSE

Exercise is understood to exert positive effects on bone. However cancellous bone has not been shown to increase with exercise. Previous results of our 1-yr observational prospective study in ovulatory women related 20% of the change in cancellous spinal bone mineral density (BMD), measured by quantitative computed tomography (QCT), to luteal phase length (the time from ovulation to menstruation, LL).

METHODS

The 66 women who documented exercise daily included normally active women (N = 23) and those who ran consistently or were increasing running in preparation for a marathon (N = 43). Exercise did not affect BMD change in the women as a whole. We re-evaluated those data to determine whether exercise-related effects on spinal cancellous BMD change in regularly cycling premenopausal women were related to ovulatory characteristics. The potential relationship of exercise to BMD change was reanalyzed by stratifying women into tertiles according to average LL documented by quantitative basal temperature analysis.

RESULTS

Repeated-measures ANOVA indicated independent positive effects of both luteal length (P = 0.001) and activity (P = 0.041). The 11 runners with LL > 10.9 d had a nonsignificant 0.5% increase in lumbar BMD while the 15 who averaged short LL (<9.9 d) experienced a significant 3.6% loss. In the runners as a group, however, kilometers run per week was negatively related to BMD change throughout (r = -0.347, P = 0.024).

CONCLUSIONS

These data are the first to indicate that, in women with regular cycles, luteal length and exercise independently and positively affect change in spinal cancellous BMD.

Effects of dehydration on exercise performance

Dehydration refers both to hypohydration (dehydration induced prior to exercise) and to exercise-induced dehydration (dehydration that develops during exercise). The latter reduces aerobic endurance performance and results in increased body temperature, heart rate, perceived exertion, and possibly increased reliance on carbohydrate as a fuel source. Although the negative effects of exercise-induced dehydration on exercise performance were clearly demonstrated in the 1940s, athletes continued to believe for years thereafter that fluid intake was not beneficial. More recently, negative effects on performance have been demonstrated with modest (<2%) dehydration, and these effects are exacerbated when the exercise is performed in a hot environment. The effects of hypohydration may vary, depending on whether it is induced through diuretics or sauna exposure, which substantially reduce plasma volume, or prior exercise, which has much less impact on plasma volume. Hypohydration reduces aerobic endurance, but its effects on muscle strength and endurance are not consistent and require further study.

Spinal bone mineral density in premenopausal vegetarian and nonvegetarian women: cross-sectional and prospective comparisons

OBJECTIVE

To compare spinal bone mineral density (BMD) and 1-year BMD change between premenopausal vegetarian and nonvegetarian women.

DESIGN

Cross-sectional comparison of spinal BMD at baseline and prospective comparison of a subsample.

SETTING

A western Canadian metropolitan area.

SUBJECTS/SAMPLES

Healthy vegetarian (n = 15 lacto-ovo-vegetarian, n = 8 vegan) and nonvegetarian (n = 22) women aged 20 to 40 years, with regular menstrual cycles and stable body weight completed baseline measurements. Twenty of these women (6 lacto-ovo-vegetarian, 5 vegan, 9 nonvegetarian) participated in repeat measurements at approximately 13 months.

STATISTICAL ANALYSES PERFORMED

Descriptive statistics, independent sample and paired t tests, 1-way analysis of variance, correlation analysis, and stepwise multiple regression were used to compare groups and to assess associations with BMD.

RESULTS

At baseline, subjects were 27.2 +/- 5.1 years old. Vegetarians had lower body mass index (21.1 +/- 2.3 vs 22.7 +/- 1.9, P < .05) and percent body fat (24.0 +/- 5.5% vs 27.4 +/- 5.1%, P < .05); they also tended to have lower BMD (1.148 +/- 0.111 g/cm2 vs 1.216 +/- 0.132 g/cm2, P = .06), although this was not apparent with weight as a covariate (P = .14). Baseline BMD was predicted by vitamin B-12 intake and total body fat (R2 = .24, P = .001). Participants in the follow-up differed only in their being older than nonparticipants. Over 1 year, mean BMD increased significantly (1.1%): by diet group, nonvegetarians' BMD increased but vegetarians' BMD was unchanged. No other monitored variables were associated with BMD change.

APPLICATIONS/CONCLUSIONS

Vegetarian women should be aware of links between low BMD and low body weight/body fat, and should maintain adequate intakes of nutrients believed to affect BMD.

Nutrition, exercise, and bone status in youth

The maximal amount of bone mass gained during growth (peak bone mass) is an important determinant of bone mass in later life and thereby an important determinant of fracture risk. Although genetic factors appear to be primary determinants of peak bone mass, environmental factors such as physical activity and nutrition also contribute. In this article, bone growth and maintenance are reviewed, and mechanisms are described whereby physical activity can affect bone mass. Studies addressing the effects of physical activity on bone status in youth are reviewed: Although conclusive data are not yet available, considerable evidence supports the importance of activity, especially activity initiated before puberty. The critical role of energy in bone growth is outlined, and studies assessing the impact of calcium intake during childhood and adolescence are reviewed. Although results of intervention trials are equivocal, other evidence supports a role for calcium intake during growth. Recommendations for physical activity and nutrition, directed to children and adolescents, are presented.

Rethinking postoperative diets for short-stay orthopedic surgery patients

OBJECTIVE

To examine postoperative meal tolerance and meal preferences of short-stay orthopedic surgery patients.

DESIGN

A patient survey was designed with input of nurses and former patients. Patient interviews focused on the first two meal trays provided, fluids offered, and perceived hunger after surgery.

SUBJECTS/SETTING

Subjects (n = 31) were adult orthopedic inpatients who were within 24 hours of surgery conducted while they were under general anesthetic and who had received at least one postoperative meal tray.

STATISTICAL ANALYSES PERFORMED

Descriptive statistical procedures were performed and chi 2 tests were used to compare responses at the first and second meals.

RESULTS

At the first meal after surgery, most patients reported adverse postoperative symptoms. Twenty-six (84%) patients had received regular meals. Fifteen (48%) patients reported eating almost nothing, yet 12 (39%) reported eating most or all food provided. Twenty-six (84%) patients thought a meal consisting of a combination of fluid and solid items would have been acceptable. At the second postoperative meal, fewer adverse symptoms were reported. Accordingly, most patients were able to eat the regular meal and considered solid food appropriate. Twenty-nine (94%) patients thought the amount of fluid provided after surgery was adequate. Eight (26%) patients reported feeling unreasonably hungry at some point after surgery.

APPLICATIONS/CONCLUSIONS

Short-stay orthopedic surgery patients recover quickly from general anesthesia; however, patients vary in postoperative symptoms, meal tolerance, and meal preferences. Findings from this survey were applied to the development of a postoperative meal protocol, now in use, that features meals containing a combination of solid and fluid items.

Lower-fat menu items in restaurants satisfy customers

OBJECTIVE

To evaluate a restaurant-based nutrition program by measuring customer satisfaction with lower-fat menu items and assessing patrons' reactions to the program.

DESIGN AND SETTING

Questionnaires to assess satisfaction with menu items were administered to patrons in eight of the nine restaurants that volunteered to participate in the nutrition program. One patron from each participating restaurant was randomly selected for a semistructured interview about nutrition programming in restaurants.

SUBJECTS

Persons dining in eight participating restaurants over a 1-week period (n = 686).

STATISTICAL ANALYSES PERFORMED

Independent samples t tests were used to compare respondents' satisfaction with lower-fat and regular menu items. Two-way analysis of variance tests were completed using overall satisfaction as the dependent variable and menu-item classification (ie, lower fat or regular) and one of eight other menu item and respondent characteristics as independent variables. Qualitative methods were used to analyze interview transcripts.

RESULTS

Of 1,127 menu items rated for satisfaction, 205 were lower fat, 878 were regular, and 44 were of unknown classification. Customers were significantly more satisfied with lower-fat than with regular menu items (P < .001). Overall satisfaction did not vary by any of the other independent variables. Interview results indicate the importance of restaurant during as an indulgent experience.

CONCLUSIONS

High satisfaction with lower-fat menu items suggests that customers will support restaurant providing such choices. Dietitians can use these findings to encourage restaurateurs to include lower-fat choices on their menus, and to assure clients that their expectations of being indulged are not incompatible with these choices.

Prevention and management of osteoporosis: consensus statements from the Scientific Advisory Board of the Osteoporosis Society of Canada. 5. Physical activity as therapy for osteoporosis

OBJECTIVE

To examine exercise as a therapy for people with osteoporosis.

OPTIONS

Immobilization, standing low-load and high-load physical activities.

OUTCOMES

Risk of injury, quality of life, risk of falls and fractures, strength and posture and pain management.

EVIDENCE

Relevant epidemiologic studies, clinical trials and reviews were examined, including the large-scale FICSIT trial in the United States, a prospective 4-year study of women enrolled in an exercise program in Toronto and the large-scale Study of Osteoporotic Fractures.

VALUES

Minimizing risk of injury and increasing quality of life were given a high value.

BENEFITS, HARMS, AND COSTS

Moderate physical activity in people with osteoporosis can reduce the risk of falls and fractures, decrease pain and improve fitness and overall quality of life. It may also stimulate bone gain and decrease bone loss. Its positive effects are an adjunct to other interventions, such as hormonal therapy. It may give patients the confidence to resume regular activity and can provide social interaction and support. During exercise programs, proper nutrition is necessary to prevent excessive weight loss and impaired immune function resulting from inadequate protein, vitamin and mineral intake.

RECOMMENDATIONS

Immobilization should be avoided if possible in anyone with osteoporosis or at increased risk for osteoporosis. Regular, moderate physical activity is recommended for those with osteoporosis. Elderly people should be assessed for risk of falling to identify those in greatest need of an exercise program. Community group exercise programs are beneficial. Younger people with osteoporosis also need exercise that will preserve or improve bone mass, muscular strength, endurance and cardiovascular fitness. Weight loss as a result of physical activity should be avoided and adequate intake of protein, vitamins and minerals assured. Because the benefits of physical activity are independent of the effect of other therapies, physical activity is an essential adjunct to appropriate nutrition and other therapies.

VALIDATION

These recommendations were developed by the Scientific Advisory Board of the Osteoporosis Society of Canada at its 1995 Consensus Conference. They are in agreement with the position taken on osteoporosis and exercise by the United States Center for Disease Control and Prevention and the American College of Sports Medicine.

SPONSORS

Sponsors of the 1995 conference included the Dairy Farmers of Canada, Eli Lilly Canada, Inc., Hoffmann-La Roche Canada Ltd., Merck Frosst Canada Inc. and Procter & Gamble Pharmaceuticals Canada Inc.

Ovulatory premenopausal women lose cancellous spinal bone: a five year prospective study

Healthy premenopausal women with regular cycles are believed to be increasing or maintaining bone density. However, few studies have prospectively documented spinal cancellous bone, the bone that changes rapidly in response to reproductive hormones, in this population. Furthermore, our previous one-year study documented that 24% of the one-year bone change by quantitative computed tomography (QCT) was related to subclinical ovulatory disturbances (short luteal phase and non-ovulation) in the presence of regular menstrual cycles. The purpose of this study was to document the cancellous bone change over five years in this initially ovulatory, premenopausal cohort of 66 healthy women. Thirty-seven women, who continued to be premenopausal and have regular cycles, completed this five-year study. Those enrolled differed only by being older and weighing less than those who could not be contacted (n = 19) or who declined to participate (n = 10). Documentation of current ovulatory characteristics was obtained for at least three cycles in 27 women. At the five-year assessment, the volunteers were 40.6 (range 26-47) years old, weighed 58.5 (41-77) kg, and were 160.9 (149-174) cm in height. All were premenopausal, healthy, nonsmokers with regular menstrual cycles (mean 27.7, range 24-33 days). Six women with intervening events (such as pregnancy or use of oral contraceptives) had interval (12 to 60 months) QCT changes similar to the remaining 31 (-7.98 vs. -4.92 mg/cm, p = 0.1, respectively). Mean five-year QCT was 143.0 +/- 20.2 mg/cm, whereas the initial mean value was 151.9 +/- 20.1 mg/cm. Significant QCT loss over five years (-8.9 +/- 6.2 mg/cm) (95% Cl -6.9 to -11.0) correlated with QCT change in the first year (r = 0.629, p < 0.001). First-year change was not related to the subsequent four-year interval change (r = -0.056, p = 0.74), however. Five-year QCT change was not related to age, weight, osteoporosis family history, estimated calcium intake, or exercise, but did correlate with year one luteal index (luteal/cycle length) (r = 0.339, p = 0.043). Significant cancellous spinal bone loss occurs in healthy, ovulatory premenopausal women, and is influenced by subclinical disturbances of ovulation.

Dieting attitudes and behavior in urban high school students: implications for calcium intake

PURPOSE

Adolescence is a time of rapid gain in bone density which may be influenced by calcium intake. This study assessed whether dieting concerns, known to be prevalent in adolescent girls, were associated with the calcium intake of adolescents of varying ethnicity.

METHODS

Students (n = 856) completed an instrument which assessed current weight, desired weight, height, age, ethnicity, calcium intake using a food frequency questionnaire, dieting concerns using the Eating Attitudes Test dieting subscale (DS), taste enjoyment of dairy products, and type of milk consumed.

RESULTS

Among 782 students with useable responses, most girls (69.1%) wanted to lose weight and most boys (54.2%) wanted to gain weight. Asian girls had lower body mass index (BMI) than Caucasians (19.3 +/- 2.1 vs 20.8 +/- 2.6 kg/m2, p < 0.05), but desired BMI did not vary by ethnicity in either girls or boys. Asian girls also had lower DS scores than Caucasians, but the difference was not significant with current BMI as a covariate. Girls' DS scores were higher than those of boys (6.3 +/- 6.5 vs 2.3 +/- 3.2, p < 0.001), and estimated calcium intakes were lower (815 +/- 528 vs 1149 +/- 701 mg/day, p < 0.001); however, DS scores were not associated with calcium intake for either sex. Especially among girls, dieting and body size concerns were associated with taste enjoyment of certain dairy products, and with the type, but not the amount, of milk consumed. Girls using skim milk had higher DS scores than those using low-fat or whole milk.

CONCLUSIONS

In this non-clinical sample, greater concern about dieting and body size did not directly compromise calcium intake but was associated with the type of milk used.

Medroxyprogesterone increases basal temperature: a placebo-controlled crossover trial in postmenopausal women

OBJECTIVE

To assess whether temperature is increased by medroxyprogesterone (MPA) and thus whether basal temperature records could be used to determine ovulation during cyclic MPA therapy.

DESIGN

A 2-month double-blind placebo-controlled crossover trial in which oral basal temperature was measured daily.

SETTING

Normal human volunteers in an academic medical environment.

SUBJECTS

Eleven postmenopausal women not taking gonadal hormones.

INTERVENTION

Medroxyprogesterone acetate (10 mg/d) or placebo, calendar days 16 to 25, with crossover.

MAIN OUTCOME MEASURES

Comparison of mean temperature days 17 to 26 during MPA versus placebo; comparison of differences between temperatures days 7 to 16 and 17 to 26 in MPA versus placebo months; and analysis for a significant monthly thermal shift.

RESULTS

The mean temperatures during MPA treatment averaged 0.27 degrees C higher than during the placebo phase and showed a significant change from pretreatment to "treatment" phases during MPA but not during placebo cycles. Eight of the MPA and one of the placebo cycles showed a shift from lower to higher temperatures days 16 to 25.

CONCLUSIONS

Medroxyprogesterone acetate has a physiological progesterone-like thermal effect. Therefore basal temperature data cannot reliably indicate ovulation during cyclic MPA administration.

Calcium intakes of adolescent female gymnasts and speed skaters: lack of association with dieting behavior

Calcium intake and its association with dieting behavior were assessed in female adolescents competing in an aesthetic and a nonaesthetic sport (gymnastics and speed skating). Athletes were 25 skaters and 32 gymnasts competing at a provincial level or higher. Calcium intake was assessed by food frequency questionnaire; dieting behavior by the Eating Attitudes Test Dieting subscale; and body composition by skinfolds, height, and weight. Mean calcium intakes of both groups of athletes exceeded Canadian recommendations, and skaters' mean intakes exceeded U.S. recommendations; however, many individuals had low intakes. Gymnasts were leaner than skaters and had lower calcium intakes, but this difference was not associated with Dieting subscale scores, which were similar between sports and were not correlated with calcium intake. Athletes had higher mean calcium intakes than normally active adolescents studied (measured with a similar protocol) and had lower Dieting subscale scores. Thus, although calcium intakes of some athletes require attention, sport participation was associated with increased intakes. Also, for these athletes, dieting behavior did not directly interfere with calcium intake.

Nutrient intakes and eating behavior scores of vegetarian and nonvegetarian women

OBJECTIVE

To compare nutrient intakes between vegetarians and nonvegetarians with similar health practices, and to assess relationships with eating behavior scores from the Three-Factor Eating Questionnaire.

DESIGN

Survey.

SETTING

Metropolitan area in western Canada.

SUBJECTS

Subjects (n = 45) were participants in a study comparing subclinical menstrual disturbances between vegetarians and nonvegetarians. To be included, women had to be 20 to 40 years old, be weight stable with a body mass index (BMI; kg/m2) of 18 to 25, be a nonsmoker, exercise 7 hours a week or less, consume one alcoholic drink or less a day, and not be using oral contraceptives. Nonvegetarians (n = 22) ate red meat three times a week or more, and vegetarians (n = 23, 8 vegans and 15 lactovegetarians) had excluded all meat, fish, and poultry for 2 years or more.

MAIN OUTCOME MEASURES

Nutrient intake assessed by three 3-day diet records; supplement use; body composition; and dietary restraint (conscious limitation of food intake), disinhibition, and hunger assessed by the Three-Factor Eating Questionnaire.

STATISTICAL ANALYSES PERFORMED

Anthropometric variables, nutrient intakes, and eating behavior scores were compared between vegetarians and nonvegetarians using unpaired t tests, and among vegans, lactovegetarians, and nonvegetarians using one-way analysis of variance and Duncan's test. Supplement use was compared using chi 2 analysis. The Pearson correlation coefficient was used to evaluate relationships between variables.

RESULTS

Diets of all women adhered closely to current nutrition recommendations. Vegetarians had lower protein and cholesterol intakes and higher percentage of energy as carbohydrate, ratio of polyunsaturated fat to saturated fat (P:S ratio), and fiber intake than nonvegetarians. Vegetarians had lower riboflavin, niacin, vitamin B-12, zinc, and sodium intakes and higher folate, vitamin C, and copper intakes. However, many differences were not apparent between the subgroup of lactovegetarians and nonvegetarians (their P:S ratios and carbohydrate, fiber, riboflavin, folate, vitamin C, and copper intakes were similar). In contrast, differences existed between the lactovegetarian and the vegan subgroups. Supplement use was similar between groups, except for greater vitamin C use by vegetarians. Vegetarians were leaner than nonvegetarians, had lower restraint scores, and had significant associations between restraint and BMI (r = .49; P < .05) and energy per kilogram body weight (r = -.60; P < .01).

APPLICATIONS/CONCLUSIONS

Current nutrition recommendations can be attained by vegetarians and nonvegetarians alike, but nutrient intakes cannot be inferred from dietary pattern. In this study, the intakes of health-conscious nonvegetarians and lactovegetarians were more similar than the intakes of lactovegetarians and vegans. Vegans' calcium and vitamin B-12 intakes may need attention. Vegetarians' lower restraint scores suggest that they are not at increased risk for eating disorders.

Energy intakes are higher during the luteal phase of ovulatory menstrual cycles

We compared energy and macronutrient intakes across the menstrual cycle in participants (n = 42) in a study that assessed the frequency of ovulatory disturbances in regularly cycling vegetarians and nonvegetarians. Women kept daily basal body temperature records for six consecutive menstrual cycles and provided 3-d diet records near the beginning, middle, and end of different cycles. On completion of the study, temperature records were quantitatively analyzed to determine whether cycles were ovulatory, and if so, the date the luteal phase began. Diet records kept near the beginning and end of cycles were matched with temperature analysis results, and women were grouped according to whether the end-of-cycle record was kept during the luteal phase of an ovulatory cycle (group 1, n = 29), or during an anovulatory cycle or before luteal phase onset of a short luteal phase cycle (group 2, n = 13). Group 1 had higher energy intakes during the luteal than during the follicular phase (9.27 +/- 2.69 vs 8.01 +/- 2.36 MJ/d, P < 0.0001), whereas intakes of group 2 did not differ across the cycle (7.91 +/- 2.18 vs 8.20 +/- 1.48 MJ/d, NS). Both groups' macronutrient intakes were similar in records kept near the beginning and end of cycles. Documentation of ovulation is necessary in studies assessing premenopausal women's energy intakes.

Vegetarian vs nonvegetarian diets, dietary restraint, and subclinical ovulatory disturbances: prospective 6-mo study

Ovulatory function was prospectively assessed over 6 mo in 23 vegetarians and 22 nonvegetarians with clinically normal menstrual cycles. Subjects were 20-40 y of age, of stable weight (body mass index, in kg/m2, of 18-25), on current diets for > or = 2 y, and not using oral contraceptives. Quantitative analysis of basal body temperature records classified cycles as normally ovulatory, short luteal phase (< 10 d), or anovulatory. Subjects completed the Three-Factor Eating Questionnaire (subjects completed the Three-Factor Eating Questionnaire (subscales for restraint, hunger, and disinhibition) and kept three 3-d food records. Vegetarians had lower BMIs (21.1 +/- 2.3 vs 22.7 +/- 1.9, P < 0.05), percentage body fat (24.0 +/- 5.5% vs 27.4 +/- 5.1%, P < 0.05), and restraint scores (6.4 +/- 4.4 vs 9.5 +/- 3.7, P < 0.05). Mean cycle lengths were similar, but vegetarians had longer luteal phase lengths (11.2 +/- 2.6 vs 9.1 +/- 3.8 d, P < 0.05). Cycle types also differed (chi 2 = 9.64, P < 0.01): vegetarians had fewer anovulatory cycles (4.6% vs 15.1% of cycles). Compared with those with restraint scores below the median, highly restrained women had fewer ovulatory cycles (3.6 +/- 2.3 vs 5.0 +/- 1.4, P < 0.05) and shorter mean luteal phase lengths (7.4 +/- 4.1 vs 10.7 +/- 3.1 d, P < 0.05). We conclude that ovulatory disturbances and restrained eating are less common among vegetarians, and that restraint influences ovulatory function.

Nutrition, dieting, and fitness messages in a magazine for adolescent women, 1970-1990

PURPOSE

This study was designed to characterize nutrition and fitness messages presented between 1970-1990 in a magazine for adolescent women; to evaluate whether these messages changed over time; and to assess the body shape portrayed as desirable, and whether this changed over time.

METHODS

A data collection form was developed to code nutrition and fitness-related written items, advertisements and recipes, and the page coverage allocated to these items. Body shape was assessed by measuring bust:waist and hip:waist ratios of photographs of models wearing bathing suits or underwear. Magazines from even years between 1970-1990 (n = 132) were coded.

RESULTS

Both nutrition-related and fitness-related coverage emphasized weight loss and physical appearance. Half the major nutrition-related articles presented a weight-loss plan, and weight loss was frequently addressed in other nutrition articles. The primary reasons presented for following a nutrition of fitness plan were to lose weight and become more attractive. Statements that the product or service would promote weight loss were found in 47% of nutrition-related advertisements. Nutrition coverage did not exhibit a net change over time, whereas fitness coverage increased (F = 6.6, p < .005), and the ratio of nutrition: fitness coverage changed from 10:1 in 1970 to 0.75:1 in 1990. Models' body shapes were less curvaceous than those in magazines for adult women, and the hip:waist ratio decreased over time (F = 7.3, p < .01).

CONCLUSIONS

The nutrition and fitness messages in this magazine for adolescent women emphasize body shape and appearance, similar to findings from adult women's magazines, and contribute to the cultural milieu in which thinness is an expectation for women. Between 1970-1990, the emphasis on fitness increased, and the body shape of models tended to become more linear.

Cyclic medroxyprogesterone treatment increases bone density: a controlled trial in active women with menstrual cycle disturbances

OBJECTIVE

Bone loss occurs in young women who experience amenorrhea or ovulatory disturbances. The purpose of this study was to determine whether bone loss could be prevented by simulating a more normal hormonal pattern, using treatment with cyclic medroxyprogesterone, with or without calcium supplementation, in physically active women with disturbed menstruation.

DESIGN

This study was a 1-year randomized, double-blind, placebo-controlled trial. Women who were stratified by menstrual cycle disturbance were randomized into four groups. The outcome variable was the change in spinal bone density measured by dual energy techniques.

SETTING

A large metropolitan area.

PARTICIPANTS

Sixty-one healthy, normal-weight physically active premenopausal women aged 21 to 45 years who experienced amenorrhea, oligomenorrhea, anovulation, or short luteal phase cycles completed the study.

INTERVENTION

Therapies were cyclic medroxyprogesterone (10 mg/day for 10 days per month) and calcium carbonate (1,000 mg/day of calcium) in four groups: (A) (n = 16) cyclic medroxyprogesterone plus calcium carbonate; (B) (n = 16) cyclic medroxyprogesterone with calcium placebo; (C) (n = 15) placebo medroxyprogesterone with active calcium; or (D) (n = 14) both medroxyprogesterone and calcium placebos.

RESULTS

The initial bone density (mean = 1.12 g/cm2) did not differ by group (P = 0.85). The 1-year bone density change was strongly related to treatment with medroxyprogesterone (P = 0.0001) and weakly to calcium (P = 0.072) treatment. Bone density increased significantly (+1.7% +/- 0.5%, +/- SEM, P = 0.004) in the medroxyprogesterone-treated groups (A and B), did not change in the calcium-treated group (C) (-0.7% +/- 0.6%, P = 0.28), and decreased on both placebos (D) (-2.0% +/- 0.6%, P = 0.005).

CONCLUSIONS

Cyclic medroxyprogesterone increased spinal bone density in physically active women experiencing amenorrhea or ovulatory disturbances. POTENTIAL CLINICAL SIGNIFICANCE: Amenorrhea, oligomenorrhea, anovulation, and short luteal phase cycles are common in premenopausal women and associated with spinal bone loss occurring at a stage of life when bone density would normally be stable or increasing. This controlled trial shows a significant gain in bone in women in the cyclic medroxyprogesterone intervention group, whereas those subjects in the placebo group lost bone. Calcium supplementation appeared to be helpful but did not reach statistical significance. The implications of these findings for the prevention of osteoporosis warrant further investigation.

Associations of social and demographic variables with calcium intakes of high school students

OBJECTIVE

To assess usual calcium intake of urban high school students and to assess the association of social and demographic variables with calcium intake.

DESIGN

A self-administered survey instrument containing the following elements: a food frequency questionnaire (FFQ) developed to estimate calcium intake; questions to elicit demographic information; and scales to reflect taste enjoyment of dairy products, social reinforcement for consumption of milk, perceptions of others' opinions about milk, and behavioral modeling of milk consumption (ie, the frequency of observing friends' and family members' use of milk). The FFQ was shown to include major sources of calcium in diets of a pretest sample (n = 130).

SETTING

Urban high schools in a metropolitan setting.

SUBJECTS/SAMPLES

Students in one class per grade level in six high schools (approximately 900 students) were asked to participate. Of the 856 questionnaires completed, 785 were usable.

MAIN OUTCOME MEASURES

Total calcium intake, as estimated using the FFQ.

STATISTICAL ANALYSES PERFORMED

Descriptive statistics, t tests, one-way analysis of variance, correlation analysis, and stepwise multiple regression analysis were used to assess relationships of independent variables with calcium intake.

RESULTS

Mean estimated calcium intakes for male and female students were 1,146 +/- 41 mg/day (mean +/- standard error of the mean) and 815 +/- 26 mg/day (P < .001), respectively, 59% of which was obtained from milk. Median intakes were 1,016 mg/day for boys and 676 mg/day for girls, and more than half the students had intakes that were below current recommendations. Multiple regression analysis revealed significant predictors of total calcium intake: gender (boys > girls); taste enjoyment of dairy products; number of meals and snacks per day; age; ethnicity (whites > Asians); behavioral modeling of milk consumption; perceptions of others' opinions, recommendations, and use of milk; and soft drink consumption (total adjusted R2 = .304). With the exception of age, these variables were positively associated with calcium intake. Regression equations developed for boys and girls separately revealed that different variables entered the equations.

APPLICATIONS/CONCLUSIONS

Most of the variability in adolescents calcium intakes remained unexplained by the variables included in this study. Nevertheless, the results suggest that education programs focusing on taste enjoyment of dairy products and building on the influence of peers and family members may have a positive impact on calcium intake.

Restrained eating and ovulatory disturbances: possible implications for bone health

We assessed the relationship between dietary restraint and menstrual cycle characteristics in 27 ovulatory women, previous participants in a longitudinal study of spinal cancellous bone mineral density (BMD). Subjects completed the restraint scale of the Three Factor Eating Questionnaire, recorded basal temperature and exercise for at least three menstrual cycles, and completed a 3-d food record. Cycle lengths of women in the upper and lower tertiles of scores for restraint were similar [27.8 +/- 1.0 (mean +/- SE) vs 27.6 +/- 0.8 d], but luteal phase length was shorter in the former group (8.6 +/- 0.9 vs 10.8 +/- 0.5 d, P < 0.05). Age, body mass index, percent body fat, waist-hip ratio, reported energy intake, and activity were similar between groups. Because the previous longitudinal study found associations between ovulatory disturbances and bone loss, we assessed spinal BMD using dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT). BMD of women in upper and lower restraint tertiles, respectively, did not differ: DXA, 1.15 +/- 0.05 vs 1.20 +/- 0.06 g/cm2; and QCT, 140 +/- 7 vs 133 +/- 7 mg/cm3. Additional prospective studies, however, appear warranted. In conclusion, this study's results provide evidence that high dietary restraint is associated with a shortened luteal phase length.

Body composition analysis of female adolescent athletes: comparing six regression equations

This study investigated whether meaningful differences occurred when percentage body fat (%BF) values were estimated for female adolescent athletes using six different regression equations found in the two of which were age-adjusted. Skinfold thickness (SF) and bioelectrical impedance analysis (BIA) measurements were taken prior to training and > or = 2 h postprandial on 29 gymnasts and 25 speed skaters who competed at a minimum of a provincial level. Mean ages were similar (14.3 +/- 1.6 yr, mean +/- SD, vs 14.3 +/- 1.5 yr); however, the speed skaters were taller (162.2 +/- 8.2 cm vs 154.0 +/- 5.0 cm, P < 0.001) and heavier (58.5 +/- 9.5 kg vs 46.0 +/- 7.9 kg, P < 0.001). Analysis of variance of %BF revealed a significant effect of sport (F(1,52) = 39.3, P < 0.001), with gymnasts having lower values. There was also a significant effect of regression equation (F(5,260) = 147.8, P < 0.001), and post-hoc comparisons revealed significant differences between almost all equations. Calculated %BF values ranged from 21.0 +/- 7.7% to 28.1 +/- 3.9% for speed skaters and from 10.3 +/- 5.3% to 22.8 +/- 3.7% for gymnasts. For both sports, the age-adjusted equations for SF and BIA produced the lowest and the highest %BF values, respectively. Our results indicate the need for caution when using field techniques to estimate %BF of female adolescent athletes. We suggest that an appropriate technique and regression equation for use with this group is the Jackson and Pollock quadratic equation for skinfolds, using Lohman's age-adjusted specific constants to correct for lower density of fat-free mass in youths.

Satisfaction of recent University of British Columbia dietetics graduates with undergraduate education and current job

This study was designed to investigate the career status of recent University of British Columbia (UBC) dietetics graduates and their satisfaction with undergraduate education and current job. All graduates from the UBC Dietetics Program between 1978-1987, inclusive (n = 238), were mailed questionnaires. Information was sought regarding success in obtaining a dietetic internship, current employment status, job satisfaction, and satisfaction with undergraduate education. Questionnaires were returned by 67% (n = 130) of those who received them. Approximately 83% were eventually successful in obtaining an internship. Most respondents (68.5%) were employed as dietitian/nutritionists, and 69% of those who were employed worked full-time. Those who interned had significantly higher salaries than those who did not. A measure of overall job satisfaction revealed that 89.6% were satisfied to very satisfied with their present job, and scores on the Brayfield-Rothe Index of Job Satisfaction revealed no differences between those who did and did not intern. With regard to undergraduate education, respondents were most satisfied with library resources, class size and quality of teaching, and least satisfied with internship opportunities. Those who had interned were significantly more satisfied with their undergraduate education than were those who had not. We conclude that success in obtaining a dietetic internship affects salary and satisfaction with undergraduate education, but does not affect job satisfaction.