Validation of a youth/adolescent food frequency questionnaire.

BACKGROUND: To address limited longitudinal nutrition data on children and adolescents, a self-administered food frequency questionnaire was designed for older children and adolescents. Initially, the Youth/Adolescent Questionnaire (YAQ) was developed and demonstrated to be reproducible. This study was conducted to evaluate its validity. METHODS: The form was administered twice to a sample of 261 youths (ages 9 to 18) at an approximate interval of 1 year (1993-1994), and three 24-hr dietary recalls were collected during this period. Pearson correlation coefficients were calculated on nutrient data. RESULTS: Validity was first evaluated by comparing the average of the three 24-hr recalls to the average of the two YAQs. Similar mean nutrients were found by both methods. Correlation coefficients between the mean energy-adjusted nutrients computed by the two methods ranged from 0.21 for sodium to 0.58 for folate. After correction for within-person error, the average correlation coefficient was 0.54, similar to that found among adults. CONCLUSION: A simple self-administered questionnaire completed by older children and adolescents can provide nutritional information about this age group.

Effects of alterations in fatty acid intake on the blood pressure of adolescents: the Exeter-Andover Project.

To judge the effect on blood pressure, the ratio of polyunsaturated to saturated fatty acids (P:S) of foods served to students at two boarding high schools was modified alternately at each school for one school year. The average P:S of the diet of males increased from 0.53 to 0.93 during the intervention whereas among females it increased from 0.64 to 0.98. Comparison of repeated systolic and diastolic blood pressure measurements near the end of the school year did not demonstrate a beneficial effect of the dietary fat changes on the blood pressure of these normotensive adolescents. Compared with the blood pressure patterns during control years, the dietary intervention resulted in slightly higher systolic (+0.88 mm Hg; 95% CI -0.66, +2.42) and diastolic (+1.23 mm Hg; 95% CI = +0.04, +2.42) blood pressure readings among males. Among females the intervention resulted in slightly lower systolic (-0.54 mm Hg; 95% CI = -1.95, +0.88) and diastolic (-0.80 mm Hg (95% CI -2.18, +0.58) blood pressure readings.

Use of fat-modified food products to change dietary fat intake of young people.

Food purchasing and preparation practices were modified in two boarding high schools to increase the polyunsaturated-to-saturated fat ratio (P/S) of the diet of students by changing food products rather than attempting to change eating behaviors. During years when fat-modified products were served, the P/S of males increased by 75 percent, versus a decrease of 6 percent during control years. For females, P/S increased by 53 percent during intervention years, versus an increase of 6 percent during control years.

Effects on blood pressure of a decrease in sodium use in institutional food preparation: the Exeter-Andover Project.

To judge the effect on blood pressure, sodium intake of students at two boarding high schools was reduced by 15-20% through changes in food purchasing and in preparation practices in the schools' kitchens. Students were not asked to change their usual eating habits. Each school served alternately as the control or intervention school for one school year. Blood pressure was monitored among 341 subjects during control years and 309 subjects during intervention years. Analysis of blood pressure differences between early in the school year and near the end of the school year, with adjustment for sex and initial blood pressure, showed the effect of the dietary intervention to be -1.7 mmHg for systolic (95% CI = -0.6, -2.9, p = 0.003) and -1.5 mmHg for diastolic pressure (95% CI = -0.6, -2.5, p = 0.002). Such modest and easily attainable changes in sodium intake, if maintained, could have a significant effect on the future risk of essential hypertension among young people.

Nonalcoholic carbonated beverage consumption and bone fractures among women former college athletes.

We report on data relating to nonalcoholic carbonated beverage consumption and bone fractures in 5,398 college alumnae, 2,622 former college athletes and 2,776 nonathletes, who responded to a detailed mailed questionnaire. A statistically significant association between nonalcoholic carbonated beverage consumption and bone fractures was found only in the former athletes, not the nonathletes. Among the athletes, the age-adjusted odds ratio (OR) for the association of drinkers (yes/no) with any fracture (yes/no) was 1.35, 95% confidence limits (CL) (1.14, 1.59). The dose-response relationship between the amount of carbonated beverages consumed daily and the number of bone fractures of the athletes was also statistically significant. Results of multiple logistic regression analysis, which included only alumnae greater than or equal to 50 years of age and which controlled for current exercise and other potential confounding factors, were as follows: (a) for athletes, the OR for the association of drinking nonalcoholic carbonated beverages and a first bone fracture at or after age 40 was 2.28, 95% CL (1.36, 3.84); (b) for all alumnae, a low milk diet was a risk factor for first bone fractures at or after age 40, OR = 1.92, 95% CL (1.15, 3.16); (c) former college athletes had a significantly lower risk of first fractures at or after age 40 than did nonathletes; OR = 0.63, 95% CL (0.40, 0.99). The deleterious effect of nonalcoholic carbonated beverage consumption on the risk of bone fractures has not been reported, as far as we know.(ABSTRACT TRUNCATED AT 250 WORDS)

The environmental component: changing school food service to promote cardiovascular health.

An environmental program directed at the food service departments of two boarding high schools has been tested in a concurrently controlled longitudinal investigation in which the intervention was applied to each school in alternate years. It has been demonstrated that changes in food purchasing and preparation practices can markedly decrease sodium and modify the fat composition of foods, and that such practices result in significant changes in the nutrient intake of students. Even without an educational component for students, who maintained their usual dietary practices, the changes by food service workers led to 15-20% less sodium intake, 20% less saturated fat intake, and an increase in the P/S ratio from 0.46 to 0.84 among students. The change in sodium intake over a school year resulted in lower blood pressure among students receiving the intervention. Adjusting for sex and baseline blood pressure, the estimated effect of the intervention on systolic pressure was -1.7 mmHg (95% C.I. -0.6, -2.9; p = 0.003); for diastolic pressure, it was -1.5 mmHg (95% C.I. -0.6, -2.5; p = 0.002). Such modifications by school food service workers are well accepted and produce very palatable foods. The widespread dissemination of such practices could favorably affect cardiovascular risk factors of students everywhere.

Sources of sodium, potassium, and energy in the diets of adolescents.

Analysis of food diaries of 200 students in two boarding high schools indicated that 30% of their average daily sodium intake was contributed by bakery foods and ready-to-eat cereals. The next most important source of sodium (24%) was a category made up of food adjuncts, snack-type foods, soups, and beverages. The largest proportion of sodium in most foods had been added during food manufacture or preparation. Salt added at the table contributed less than 1% of the sodium in the diets of the teenagers. All students did not eat foods from all categories on their day of recording; 70% or more ate bakery products, dairy foods, food adjuncts, and meat, fish, poultry, and eggs. Changes in recipe formulations can decrease sodium content for a variety of bakery products, cereals, mixed dishes, snack-type foods, soups, and processed meats. It is therefore possible to make large reductions in dietary sodium without disturbing other nutrient values.

Lower lifetime occurrence of breast cancer and cancers of the reproductive system among former college athletes.

The prevalence (lifetime occurrence) rate of cancers of the reproductive system (uterus, ovary, cervix, and vagina) and breast was determined for 5,398 living college alumnae, 2,622 of whom were former college athletes and 2,776 nonathletes, from data on medical and reproductive history, athletic training, and diet. The former athletes had a significantly lower risk of cancer of the breast and reproductive system than did the nonathletes. The relative risk (RR), nonathletes/athletes, for cancers of the reproductive system was 2.53, 95% confidence limits (CL) (1.17, 5.47). The RR for breast cancer was 1.86, 95% CL (1.00, 3.47). The analysis controlled for potential confounding factors, including age, family history of cancer, age at menarche, number of pregnancies, use of oral contraceptives, use of estrogen in the menopausal period, smoking, and leanness. Of the college athletes, 82.4% had been on precollege teams compared with 24.9% of the college nonathletes. We conclude that long-term athletic training lowers the risk of breast cancer and cancers of the reproductive system. The lowered risk may be related to changes in estrogen metabolism associated with increased leanness.

Lower prevalence of breast cancer and cancers of the reproductive system among former college athletes compared to non-athletes.

The prevalence (lifetime occurrence) rate of cancers of the reproductive system (uterus, ovary, cervix and vagina) and breast cancer was determined for 5,398 living alumnae, 2,622 of whom were former college athletes and 2,776 non-athletes, from data on medical and reproductive history, athletic training and diet. The former athletes had a significantly lower risk of cancer of the breast and reproductive system than did the non-athletes. The relative risk (RR), non-athletes/athletes, for cancers of the reproductive system was 2.53. 95% confidence limits (CL) (1.17, 5.47). The RR for breast cancer was 1.86, 95% CL (1.00, 3.47). The analysis controlled for potential confounding factors including age, family history of cancer, age of menarche, number of pregnancies, use of oral contraceptives, use of oestrogen in the menopausal period, smoking, and leanness. Of the college athletes, 82.4% had been on pre-college teams compared to 24.9% of the college non-athletes. We conclude that long term athletic training may lower the risk of breast cancer and cancers of the reproductive system.

Dietary sodium reduction among students: feasibility and acceptance.

Modifications in the preparation of food served in a boarding high school during a 5-week period were successful in decreasing the sodium content of a variety of food products by an average of 51%. Such food was, in general, well accepted. The ratings of specific reduced-sodium food products equaled those of similar products containing "usual" amounts of sodium. Food diaries kept by students gave estimates of total sodium intake comparable with those measured by laboratory analysis of 24-hour food collections. Food diaries collected from an average of 70 volunteers per week indicated that during the reduced-sodium period, the total sodium intake of students, including that from dining hall food, snack food, and food consumed outside the school, decreased from 136 mEq (3 gm sodium, 8 gm salt) to 88 mEq (2 gm sodium, 5 gm salt), a reduction of 35% (p less than .0001). The impact of salt added at the table was very small; the choice and the quantity of foods consumed were the main determinants of sodium intake. The results indicate that foods can be prepared with appreciably less sodium and still be highly acceptable to young people.

Reproducibility and validity of a semiquantitative food frequency questionnaire.

The aim of this study was to evaluate the reproducibility and validity of a 61-item semiquantitative food frequency questionnaire used in a large prospective study among women. This form was administered twice to 173 participants at an interval of approximately one year (1980-1981), and four one-week diet records for each subject were collected during that period. Intraclass correlation coefficients for nutrient intakes estimated by the one-week diet records (range = 0.41 for total vitamin A without supplements to 0.79 for vitamin B6 with supplements) were similar to those computed from the questionnaire (range = 0.49 for total vitamin A without supplements to 0.71 for sucrose), indicating that these methods were generally comparable with respect to reproducibility. With the exception of sucrose and total carbohydrate, nutrient intakes from the diet records tended to correlate more strongly with those computed from the questionnaire after adjustment for total caloric intake. Correlation coefficients between the mean calorie-adjusted intakes from the four one-week diet records and those from the questionnaire completed after the diet records ranged from 0.36 for vitamin A without supplements to 0.75 for vitamin C with supplements. Overall, 48% of subjects in the lowest quintile of calorie-adjusted intake computed from the diet records were also in the lowest questionnaire quintile, and 74% were in the lowest one of two questionnaire quintiles. Similarly, 49% of those in the highest diet record quintile were also in the highest questionnaire quintile, and 77% were in the highest one or two questionnaire quintiles. These data indicate that a simple self-administered dietary questionnaire can provide useful information about individual nutrient intakes over a one-year period.

Delayed menarche and amenorrhea of college athletes in relation to age of onset of training.

Age at menarche and menstrual periodicity of 21 college swimmers and 17 runners were studied in relation to the age of initiating training. The 18 premenarche-trained athletes had a mean menarcheal age of 15.1 +/- 0.5 years, whereas the 20 postmenarche-trained athletes had a mean menarcheal age of 12.8 +/- 0.2 years, similar to that of the college control subjects, 12.7 +/- 0.4 years. Each year of training before menarche delayed menarche by five months (0.4 years). Of the premenarche-trained athletes, 61% had irregular menstrual cycles and 22% were amenorrheic, whereas 60% of the postmenarche-trained athletes had regular menstrual cycles and none were amenorrheic. Training increased the incidence of oligomenorrhea and amenorrhea among both premenarche- and postmenarche-trained athletes. Metabolic and hormonal changes consequent to an increased lean/fat ratio may explain these findings.

Analysis of dietary data; an interactive computer method for storage and retrieval.

The authors briefly review some problems encountered in collecting and interpreting dietary data and in analyzing them by hand and by computer methods. The use of computers, meant to speed processing, has often delayed processing or merely replaced computation time with coding time. The authors describe a simplified nutrient data base and an interactive retrieval method, Quick Input of Food, which has been developed for direct use by nutritionists with their clients.

Family cooperation and effectiveness in a cholesterol-lowering diet.

An average reduction in serum cholesterol approximating 10 per cent was achieved in a short-term, family-centered study in which intakes of cholesterol and saturated fats were decreased and sunflower oil and margarine were added as the major sources of polyunsaturated fats. Dietary Achievement Scores demonstrated shifts in food consumption between baseline and diet periods. Changes were evident in all fat-containing food groups; meat was the least altered. A high degree of cooperation was evident in participating families, implying the possibilities for complete family cooperation in preventive or therapeutic dietary programs. Approximately three months after the end of the test period, cholesterol levels had returned to pre-diet levels, indicating the need for continuation of the changed regimen if cholesterol-lowering is to be maintained.

Dietary interviewing by computer. An experimental approach to counseling.

A computer-based dietary counseling system was tested by sixty-four volunteers from the Boston area. Most of the patients seemed to benefit from their interaction with the computer, and the two participating nutritionists frequently found that the program was useful as an antecedent to their own one-to-one sessions with the patients.