Abstract
The combination of poor diet and exposure to secondhand smoke may increase hemoglobin A1c (HbA1c) levels, but few studies have explored this interaction. We explored an interaction among 574 never-smoking adults from the Singapore Chinese Health Study. At baseline (age 59 ± 8 years), intakes of omega-3 polyunsaturated fatty acids, vitamin C, vitamin E and fiber were estimated using a modified food frequency questionnaire. At follow-up (age 64 ± 9 years), HbA1c and cotinine were measured. A product term between cotinine (above or below the median value) and each nutrient (high or low intake) was included in separate linear regression models with HbA1c as the outcome. HbA1c among those with high cotinine and low omega-3 polyunsaturated fatty acids intakes were higher than would be expected due to the individual effects alone (p-for-interaction = 0.05). Among those with lower intakes of omega-3 polyunsaturated fatty acids, high cotinine levels were associated with 0.54% higher HbA1c levels (95% confidence interval [CI]: 0.02, 1.06). Conversely, among those with higher intakes of omega-3 polyunsaturated fatty acids, HbA1c differ not differ by exposure (−0.09%; 95% CI: −0.45, 0.30). No evidence of interaction was observed for other nutrients. Diets high in omega-3 polyunsaturated fatty acids may ameliorate secondhand smoke-induced increases in HbA1c.
Original language | English (US) |
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Article number | 5148 |
Journal | International journal of environmental research and public health |
Volume | 16 |
Issue number | 24 |
DOIs | |
State | Published - Dec 2 2019 |
Bibliographical note
Funding Information:Funding: This work was partially supported by the American Heart Association Beginning Grant-in-Aid [Clark, 12BGIA11910040]. Agus Salim’s work on developing methods for secondary analysis of nested case-control data was partially funded by the National Health and Medical Research Council [NHMRC, 1108967]. The Singapore Chinese Health Study was supported by the U.S. National Institutes of Health grants R01 CA144034 and UM1 CA182876.
Funding Information:
This work was partially supported by the American Heart Association Beginning Grant-in-Aid [Clark, 12BGIA11910040]. Agus Salim?s work on developing methods for secondary analysis of nested case-control data was partially funded by the National Health and Medical Research Council [NHMRC, 1108967]. The Singapore Chinese Health Study was supported by the U.S. National Institutes of Health grants R01 CA144034 and UM1 CA182876. We thank Siew-Hong Low of the National University of Singapore for supervising the fieldwork of the Singapore Chinese Health Study. We also thank Rob M. van Dam for developing and providing the dataset from the nested case-control study utilized here. Finally, we acknowledge Mimi C. Yu, the founding, long-standing principal investigator of the Singapore Chinese Health Study.
Publisher Copyright:
© 2019 by the authors. Licensee MDPI, Basel, Switzerland.
Keywords
- Antioxidants
- Cotinine
- Diet
- HbA1c
- Interaction
- Omega-3 polyunsaturated fatty acids