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Eating habits, physical activity and risky behaviors of youth

practicing weight control

Julie Chmielewski

M.S. Candidate

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Objective

1. Evaluate a nationally representative sample of adolescents to determine the prevalence of weight control methods according to youth’s weight status.

2. Confirm that overweight youth are using recommended methods of weight control according to Healthy People 2010.

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Rationale•Obesity

NHANES 11%, YRBS 16% •Weight control

YRBS 43% of youth•Health consequences of inappropriate weight control

Growth retardation, acute gastric dilation, metabolic alkalosis, cardiac arrhythmia, death•Risky health behaviors associated with wt. control

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Data

• National Longitudinal Study of Adolescent Health (Add Health) – Chapel Hill, N.C.

• Funded by: National Institute of Child Health and Human Development & 17 other agencies

• Wave II from 1995-1996• Major topics: nutrition, daily activity, health

service use, violence, sexual behavior, substance abuse, injury

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Data source

                                             

                      

                                             

News Search Site Map Contact Us

© 1998 The National Longitudinal Study of Adolescent HealthLast modified 28 April 2000

http://www.cpc.unc.edu/projects/addhealth/addhealth_home.html

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Research Question #1

a. What is the frequency of weight control use among adolescents who have already started puberty and grouped by underweight, average weight or overweight/obese?

b. Are there differences in frequency of weight control use among pubescent youth by weight category, grade, race and age categories?

c. What types of weight control methods are used?

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Research Question #2a. Are pubescent youth who use weight control

methods at increased risk for participating in other risky health behaviors such as smoking, drug use, alcohol consumption and/ or suicide thoughts?

b. Is there a difference in risky health behaviors among pubescent youth who use weight control as grouped by weight category?

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Research Question #3

Do underweight, average weight and overweight pubescent youth who use weight control methods have healthy eating and exercise behaviors (as recommended by HP2010)?

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Variable selection (n=13, 568)

Menarche YES

Sexual Maturation

Stage 3YES

Underweight Average Overweight Underweight Average Overweight

Nutrition

Fast FoodBeverage Breakfast

Food GroupsPhysical Activities

Risky behavior (Yes/No) – suicide, substance use, tobacco use, drug use, dangerous weight control

Types of weight control behaviors – diet, exercise, laxative, vomiting, diet pills

Health-promoting Behaviors

Weight Control(Yes/No)

Weight Control(Yes/No)

Weight Control(Yes/No)

Weight Control(Yes/No)

Weight Control(Yes/No)

Weight Control(Yes/No)

MalesFemales

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Definitions

Weight control: includes everything reported to lose weight or to keep from gaining weight

Dangerous weight control: using vomiting, diet pills, or laxatives to lose weight or keep from gaining weight

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Definitions

Weight categories: calculated from measured height and weights and BMIs compared to age- and gender-specific growth charts for underweight, average weight, at risk for overweight, overweight

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2000 NCHS

Growth Chart

95th

85th

5th

95th

85th

5th

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Definitions

Puberty status:

1) boys secondary sex characteristics

2) girls - menarche

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How puberty status determined for boys in Add Health Wave II Sexual Maturation Stagea Question from Add Health Stage 1 Prepubescent No hair under arms at all.

No hairs on face. Voice not lower.

Stage 2 Pubic hair appears Genitalia growth Sweat gland action

I have little facial and underarm hair. Yes, voice is a little lower than grade school.

Stage 3 Pubic hair extends Genitalia growth Begin acne Voice changes

I have some underarm hair, but not a lot. The hair is thick on my face. My voice is somewhat lower than grade school.

Stage 4 Pubic hair thickens Genitalia growth Acne may be severe Voice deepens

I have lots of hair under my arms and it is thick. The hair is thick on my face like a grown man’s. Yes my voice is a lot lower than grade school.

Stage 5 Hair distribution increases Genitalia fully mature Acne may persist or increase

I have a whole lot of hair that is very thick, as much underarm hair as a grown man.

The hair is very thick, like a grown man’s facial hair.

My voice is a whole lot lower than when I was in grade school; it is as low as an adult man’s voice.

aTanner, 1984

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Analyses

• SPSS – Statistical Package for Social Sciences

• SUDAAN statistical analysis software• Cross tabulations & Logistic Regression• Odds ratios and confidence intervals

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Demographic characteristics (N=11,012) Girls Boys

Characteristics No.

% Yes, Wt. Control

(weighted %) No.

% Yes, wt. Control

(weighted %) Adolescent Total 6063 100 74 4958 100 44 Weight category *** *** Underweight 161 3 31 119 2 30 Average weight 4115 69 77 3328 68 46 Overweight 922 15 91 722 15 70 Obese 741 13 94 757 15 86

Age category *** <14 years 1120 18 82 769 16 63 15-16 years 2459 41 81 1941 39 56 17-18 years 2484 41 78 2248 45 51

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Demographic characteristics (N=11,012) cont. Girls Boys

Characteristics No.

% Yes, Wt. Control

(weighted %) No.

% Yes, wt. Control

(weighted %) Adolescent Total 6063 100 74 4958 100 44 Ethnicity ** ** White 3315 55 82 2887 58 57 African American

1379 23 78 857 17 46

American Indian 95 2 80 75 2 56 Asian 373 6 71 355 7 58 Hispanic 844 14 77 740 15 59 Other 48 1 74 40 1 57

Grade * 9th or younger 1903 34 81 1438 31 60 10th grade 1202 21 83 1000 22 57 11th grade 1313 23 78 1183 25 53 12th or beyond 1236 22 79 1010 22 52

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Privacy issue with weight control questions

When 20% of participants reported a third person in the room -

• Girls less likely to report dieting or diet pill use• Boys less likely to report diet pill use

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Type of weight control used by adolescents

Girls (n=4777) Boys (n=2182)

Exercise 43% 52%

Dieting and exercise

18% 9%

Dieting alone 7% 3%

Laxatives, vomiting, diet pills*

3% <1%

* 50% girls using these methods were average weight.

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Logistic regression analyses of demographic variables by wt control Girls (n=4094) Boys (n=3861) OR 95% CI OR 95% CI

Weight Category Average weight 1.0 1.00/1.00 1.0 1.00/1.00 Underweight 0.1** 0.04/.015 0.2** 0.07/0.37 Overweight 3.6** 2.50/5.23 3.9** 2.96/5.02 Obese 5.6** 3.45/9.18 11.5** 8.54/15.60 Ethnicity White 1.0 1.00/1.00 1.0 1.00/1.00 African American 0.6** 0.47/0.79 0.5* 0.32/0.97 Hispanic 0.6* 0.44/0.86 1.2 0.81/2.02 Other 0.7* 0.48/0.98 1.4 0.91/2.14 Age category <=14 years 1.0 1.00/1.00 1.0 1.00/1.00 15-16 years 1.1 0.79/1.44 0.4** 0.22/0.65 >=17 years 0.8 0.53/1.28 0.4* 0.20/0.92

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Eating and exercise behaviors

• Fruit & vegetable intake: 5+ servings• Milk intake: > 1 serving milk• Fast food intake: < 2 times per week• Breakfast intake: > 5 times a week and 3 or

more food groups• Variety of food: 1 serving of each food group• Exercise: > 3 times a week for > 30 minutes

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GIRLS: Eating and exercise behaviors associated with weight control

Positive behaviors• 1.6 x more likely to eat less fast food• 1.6 x more likely to get exercise > 3x/wk for 30 min.• Less likely to use drugsNegative behaviors• 1.4 x more likely to eat an inadequate breakfast• 1.6 x more likely to skip breakfast• 1.6 x more likely to consume alcoholNot significant • Fruit and vegetable intake, dairy, food group variety

* Odds ratios reported were significant.

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BOYS: Eating and exercise behaviors associated with weight control

Positive behaviors• 1.9 x more likely to eat less fast food

Negative behaviors• No significant findings

Not significant • Fruit and vegetable intake, dairy, food group

variety, breakfast consumption, exercise

ns = not significant 24

Likelihood of weight control (after controlling for all these variables)

Odds ratio; p<0.05 Average Weight Overweight

Girls Boys Girls Boys

Fast food (< 2x/wk) 1.6 2.1 ns Ns

Inadequate Breakfast ns ns 2.3 ns

Exercise (3x/wk@30min)

1.6 ns ns ns

African American 0.5 0.37 ns ns

Grade1.8 (11th )

2.6 (12th)2.5 (10th)

0.2 (11th )

0.1 (12th )0.4 (11th ) 0.2 (12th )

Age (yr) 2.6 (17+) 0.3 (15-16) ns ns

Alcohol (yes) 1.6 ns 2.2 ns

Drug (yes) 0.6 ns 0.4 ns

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ConclusionsHealth People 2010:Overweight adolescents should be practicing

adequate exercise and eating a balanced diet.

89% overweight youth using weight control– OW boys eating less fast food– OW girls eating inadequate breakfast– 49% of those using dangerous weight control

methods were OW

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Conclusions55% of average wt. youth using weight control

– AW girls less likely to eat fast food and more likely to exercise

– AW boys less likely to eat fast food– 51% of those using dangerous methods were

AW

30% of underweight youth using weight control

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Thank youDr. Hoerr

Dr. Weatherspoon

Dr. Kallen

My parents

My lab group

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