According to a 2009 review published in Osteoporosis International there is no evidence linking caffeine intake to a low Bone Mineral Density (BMD) in women approaching the menopause or recently menopausal. (Click here to know the amount of caffeine tea contains)
Osteoporosis and BMD:
Low BMD is a characteristic of Osteoporosis, a condition where the bones become thin and weak thereby increasing the risk of fractures. Osteoporosis is a major health problem worldwide with more than 75 million people in Europe, Japan and the United States being affected. Every year it causes 2.3 million fractures in Europe and the United States. In the UK one in two women and one in five men over the age of 50 will fracture a bone, mainly as a result of osteoporosis.
Bone loss occurs when estrogen levels decline and as a result Osteoporosis mainly affects women after the age of menopause. Identifying younger women who are potentially at risk of low BMD will help to determine those who may benefit from early intervention. However current risk assessment for low BMD is mainly based on data of older women (≥ 65 years of age) which may not be relevant to younger women. The aim of this current study was to review the scientific evidence to identify risk factors for low BMD in healthy women aged 40 to 60 years.
A literature search was performed to identify the studies that examined risk factors associated with low BMD in women aged 40 to 60 years. Observational studies, as well as articles that evaluated clinical assessment tools, were included if BMD was measured using dual energy x-ray absorptiometry (DXA). Randomized controlled drug trials, case series, case reports, letters, editorials or reviews were excluded. These studies were then screened to assess their eligibility.
Research About Risk Factors for Low BMD:
Thirteen studies met all the eligibility criteria and were included in the final review. Thirteen risk factors for low BMD were identified:
- Physical Activity
- Alcohol Consumption
- Caffeine intake
- Age at menarche
- Reproductive history
- History of pre-menopausal amenorrhea
- Menopausal status or years post menopause
- Family history of Osteoporosis
- Older age (independent of menopausal status)
- Body Weight
The strength of the evidence for an association between each risk factor and BMD was then graded as good, fair, inconsistent or insufficient. This was determined by the quality of the study, the number of studies assessing a particular risk factor and the consistency of the results:
- Good – good evidence for or against an association between the risk factor and BMD (consistent results across studies; more than 3 studies; at least 1 study graded as ‘good quality’ using the U.S. Preventive Services Task Force guidelines)
- Fair – fair evidence for or against an association between the risk factor and BMD (consistent results across studies but limited by quantity (≤ 3 studies) or quality (no studies graded as ‘good’))
- Inconsistent – inconsistent evidence for or against an association between the risk factor and BMD (studies had conflicting results)
- Insufficient – insufficient evidence for or against an association between the risk factor and BMD (inadequate number of studies – less than 3 studies)
Study Results on Caffeine Intake and Low BMD:
Three studies evaluated the relationship between current caffeine intake and BMD, and one also examined lifetime intake. Sources of caffeine in these studies were from coffee, tea and cola, although no details were provided on the amounts of caffeine. An association between caffeine intake and BMD was not detected in any study. Using the grading criteria, the evidence that current caffeine intake is not associated with BMD was graded as ‘fair’ while there is insufficient evidence for an association between past intake and BMD.
The researchers concluded by saying while there is good evidence that menopausal status is associated with BMD, out of all the risk factors examined, only low body weight can be considered, with confidence, as an important risk factor for low BMD in healthy 40 to 60 year old women. In terms of caffeine, this review found no evidence of an association between caffeine intake and lower BMD.
Waugh EJ et al (2009) Risk factors for low bone mass in healthy 40-60 year old women: A systematic review of the literature.
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