Cross-sectional studycited by the Tayebat archiveabstract only checked★ key study A-SOD-03 in-depth review

Cola and bone density in older women

Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study.

Overview

Tucker KL et al.. Am J Clin Nutr 2006 · PMID 17023723 · DOI 10.1093/ajcn/84.4.936

Women drinking cola daily had 3.7% lower hip bone density; other fizzy drinks showed no link.

Does the study support the specific claim? Partly · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Is cola consumption associated with lower BMD?
How was the study done?: Cross-sectional analysis of BMD (DXA) by FFQ soft-drink frequency, Framingham Osteoporosis Study.
How many people, animals or samples were studied?: 1,413 women; 1,125 men; Older women and men
What was actually found?: Women: cola associated with lower BMD at each hip site (P<0.001-0.05) but not spine; daily intake 3.7% lower femoral neck and 5.4% lower Ward's area BMD; similar for diet cola; no association in men or for non-cola carbonated beverages; phosphorus intake not significantly higher in daily cola drinkers.
How large was the observed effect?: -3.7% femoral neck BMD (daily vs <1/month)
What do the results mean in everyday life?: Possible small effect on bone in women; not shown for other fizzy drinks.
What are the study's limitations?: Cross-sectional; Effect only in women and at hip; Mechanism not demonstrated (phosphorus intake similar); Self-reported intake
What does it say about Elawady's specific claim?: Main evidence for C-SOD-08; also limits C-SOD-14 (no association for non-cola carbonated drinks).
Do the results apply to Germany and Europe?: Moderate.
What can explicitly not be concluded from this study?: That phosphoric acid causes bone loss or fractures.

Is cola consumption associated with lower BMD?

Study design: Cross-sectional study – Cross-sectional analysis of BMD (DXA) by FFQ soft-drink frequency, Framingham Osteoporosis Study.
Population: Older women and men
Country: USA
Period: Not stated in abstract
Sample size: 1,413 women; 1,125 men
Inclusion and exclusion criteria: not stated in abstract

Exposure / intervention: Frequency of cola and other carbonated beverages
Comparator: <1 serving cola/month
Endpoints: BMD at spine and 3 hip sites
Statistical methods: Linear regression adjusted for BMI, height, age, energy, physical activity, smoking, alcohol, calcium, vitamin D, non-cola caffeine, season, menopause, oestrogen

Results: Women: cola associated with lower BMD at each hip site (P<0.001-0.05) but not spine; daily intake 3.7% lower femoral neck and 5.4% lower Ward's area BMD; similar for diet cola; no association in men or for non-cola carbonated beverages; phosphorus intake not significantly higher in daily cola drinkers.
Absolute risks: not applicable
Authors' conclusion: Intake of cola, but not of other carbonated soft drinks, is associated with low BMD in women. Additional research is needed.

Orienting tool: ROBINS-E
Type of assessment: simplified assessment (abstract only)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Confounding and temporality issues inherent to cross-sectional design.

Differences of 3.7-5.4% in BMD are modest; fracture outcomes not studied.

Main evidence for C-SOD-08; also limits C-SOD-14 (no association for non-cola carbonated drinks).

No association in men; I-SOD-07 observational only.

Moderate.

Suggestive association in women; not proof of a bone-draining effect.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	mixed
Regional transferability	moderate
Adequacy of the interpretation (by the archive)	partly correct but over-interpreted

Fracture risk; mechanism.

Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.

What the archive says about the study: Women who drink cola daily — sugary or diet — have significantly lower hip BMD, independent of age, calcium or vitamin D.
A. What was actually studied?: Association between soft-drink type and BMD.
B. What did the authors find?: Lower hip BMD in women drinking cola; not in men; not for non-cola drinks.
C. What conclusions do the authors themselves draw?: Cola, not other carbonated drinks, associated with low BMD in women; needs confirmation.
D. What does the archive derive from it?: 'Phosphoric acid drains bone'.
E. Is this derivation scientifically justified?: Numbers correct; the phosphoric-acid mechanism and the causal verb go beyond the data, especially as phosphorus intake was not higher.
Adequacy of the interpretation (by the archive): partly correct but over-interpreted