Primary Research · 2009
The effects of four weeks of creatine and beta-alanine supplementation on cardiorespiratory fitness
Graef et al. · Journal of the International Society of Sports Nutrition, 2009
Key finding
4 weeks of beta-alanine improved ventilatory threshold and endurance markers in recreationally active men.
Abstract
PubMed · PMID 19954576 →OBJECTIVE: Various studies in the USA and Canada have consistently shown a positive association between length of residence of immigrants and obesity. Studies in European countries have obtained less consistent results. The present work assesses the influence of length of residence on the frequency of obesity in immigrants in the city of Madrid, Spain. DESIGN: We studied a sample of 7155 persons aged 18 years and over residing in the city of Madrid, who were was surveyed between November 2004 and May 2005. Information was collected on immigrant status (country of birth), length of residence in Spain, obesity, sociodemographic characteristics and lifestyle. RESULTS: Compared with the Spanish population, the odds for obesity in the immigrant population by length of residence was less than one in all groups, becoming closer to one with increasing time of residence (OR = 0.67, 0.73 and 0.81 for immigrants with less than 2, 2-4 and 5-9 years of residence in Spain, respectively), up to 10 or more years of residence, when it declined (OR = 0.69). The magnitude of this association was considerably reduced after adjusting for sociodemographic variables and for perceived health, but was not further modified after adjusting for lifestyle variables. CONCLUSIONS: Length of residence of immigrants in the city of Madrid is not associated with the frequency of obesity. It is possible that the circumstances immigrants encounter after arriving in Spain do not involve an overexposure to factors favouring obesity, relative to those they bring with them.
Abstract sourced from PubMed, a database of the U.S. National Library of Medicine. Displayed in the authors’ own words for context; our critique is in the sections below.
Read the full paper
Cited in 2 guides
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How to read a study like this
The same questions worth asking about any research paper, not just this one. Worth a minute even if you trust the grade.
Who was studied, and do you resemble them?
Supplement effects often depend on baseline status. Vitamin D helps people who are deficient; iron helps people who are anemic. A result in people unlike you may not apply to you.
What was measured, and does it matter in daily life?
A study that shows a blood marker moved isn't the same as a study that shows people felt or functioned better. Ask what the outcome means in practice.
How large was the effect — not just whether it was significant.
'Statistically significant' only means the effect is unlikely to be zero. It doesn't tell you the effect is large enough to notice. Look for effect sizes, not just p-values.
Who paid for the trial, and what did they stand to gain?
Industry-funded trials are several times more likely to report positive results than independent ones. It's not usually fraud — it's subtle design and reporting choices. Weight accordingly.
Has anyone else replicated this?
Single positive trials are hypotheses. Replication by independent groups is what turns a hypothesis into reliable evidence. If the only positive trial is the one you're reading, wait.
Does the dose in the trial match what's being sold?
Supplement marketing routinely cites trials that used 5–10× the dose in the product. If the effective dose was 2 g/day and the capsule has 200 mg, expect roughly no effect.
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