Dietary calcium intake protects women consuming oral contraceptives from spine and hip bone loss.
BACKGROUND
It is estimated that 80% of all women have used oral contraceptives (OCP), but OCP use may prevent attainment of maximal peak bone mass in young women and thus increase the risk of osteoporosis later in life.


OBJECTIVE
This study examined whether increased calcium intake could reduce the detrimental effects of OCP use on bone mass in young women.


METHODS
The study design was a 1-yr intervention.


METHODS
The study was performed in a general community setting.


METHODS
One hundred fifty-four young (18-30 yr old) healthy women with a dietary calcium intake of less than 800 mg/d began the study, and 135 completed the trial.


METHODS
Subjects were randomly assigned to one of three diet intervention groups: 1) control, continuous established (<800 mg/d) dietary calcium intake; 2) medium dairy, increase calcium intake to approximately 1000-1100 mg/d; and 3) high dairy, increase calcium intake to approximately 1200-1300 mg/d. Randomization was stratified by OCP use.


METHODS
The main outcome measures were total body bone mineral density (BMD) and content (BMC); total hip BMD, BMC, and bone area; and spine BMD, BMC, and bone area.


RESULTS
Dairy product intervention positively impacted the percentage change in total hip BMD and BMC. In addition, dairy product intake prevented a negative percentage change in total hip and spine BMD in OCP users.


CONCLUSIONS
Dairy product intake, at levels necessary to achieve the recommended intakes of calcium, protected the total hip BMD and spine BMD from loss observed in young healthy women with low calcium intakes who were using OCP.
Teegarden
Dorothy
D
Interdepartmental Nutrition Program, 700 West State Street, Stone Hall-1264, Purdue University, West Lafayette, Indiana 47907, USA. dteegard@purdue.edu
Legowski
Pamela
P
Gunther
Carolyn W
CW
McCabe
George P
GP
Peacock
Munro
M
Lyle
Roseann M
RM
D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000627:therapeutic use; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D010024:Osteoporosis / Q000139:chemically induced* / Q000517:prevention & control*; D016037:Single-Blind Method; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism
D002136:Calcium, Dietary; D003276:Contraceptives, Oral