Dietary nutrients associated with preservation of lung function in Hispanic and non-Hispanic white smokers from New Mexico

Abstract

Background

COPD is the third leading cause of death in the United States. Cigarette smoking accelerates the age-related forced expiratory volume in 1 s (FEV₁) decline, an important determinant for the genesis of COPD. Hispanic smokers have lower COPD prevalence and FEV₁ decline than non-Hispanic whites (NHWs).

Patients and methods

A nutritional epidemiological study was conducted in the Lovelace Smokers cohort (LSC; n=1,829) and the Veterans Smokers cohort (n=508) to identify dietary nutrients (n=139) associated with average FEV₁ and its decline and to assess whether nutrient intakes could explain ethnic disparity in FEV₁ decline between Hispanics and NHW smokers.

Results

Nutrients discovered and replicated to be significantly associated with better average FEV₁ included magnesium, folate, niacin, vitamins A and D, eicosenoic fatty acid (20:1n9), eicosapentaenoic acid (20:5n3), docosapentaenoic acid (DPA; 22:5n3), docosahexaenoic acid (22:6n3), and fiber. In addition, greater intakes of eicosenoic fatty acid and DPA were associated with slower FEV₁ decline in the LSC. Among omega 3 polyunsaturated fatty acids, DPA is the most potent nutrient associated with better average FEV₁ and slower FEV₁ decline. Adverse effect of continuous current smoking on FEV₁ decline was completely negated in LSC members with high DPA intake (>20 mg/day). Slower FEV₁ decline in Hispanics compared to NHWs may be due to the greater protection of eicosenoic fatty acid and DPA for FEV₁ decline rather than greater intake of protective nutrients in this ethnic group.

Conclusion

The protective nutrients for the preservation of FEV₁ in ever smokers could lay foundation for designing individualized nutritional intervention targeting “optimal physiological levels” in human to improve lung function in ever smokers. Ethnic disparity in FEV₁ decline may be explained by difference in magnitude of protection of dietary intakes of eicosenoic fatty acid and DPA between Hispanics and NHWs.

Keywords:

• nutrientomics
• spirometry
• ethnic disparity

Supplementary materials

Methods

Baseline dietary assessment

Cohort members completed the adult English version of validated Harvard Food Frequency Questionnaire (FFQ), a self-administered instrument that includeŝ150 food items distributed within the eight major dietary categories, at the study entry.¹ The FFQ collects the consumption frequency and serving size of each specified food item during the past 12 months and has good coverage for food items of the US Southwestern style. The FFQ also has open-ended questions that collect use of food items consumed at least once per week but not listed in the eight major dietary categories. The validity of the application of the FFQ in New Mexico Hispanics was further supported by the results from a previous study that compared the energy and nutrient source between elderly Hispanics and non-Hispanic whites (NHWs) in New Mexico and identified no exclusive pattern for consumption of Southwestern regional foods in Hispanics compared to NHWs.² In addition, the estimated consumption of vitamins A and C in the current study was highly comparable to the data from a study that itemized all chili-containing traditional Southwestern foods commonly consumed in New Mexico, suggesting the sufficiency of Harvard FFQ in capturing the chili-derived nutrients.² Furthermore, serum vitamins B12 and C and folate levels were reported to be significantly lower in Hispanics versus NHWs in a previous study of an elderly New Mexican population.³ These three vitamins also showed the ethnic difference in the dietary assessment (not shown). Estimates of daily nutrient intakes are derived by summing over all foods the products of the reported frequency of each food by the amount of nutrient in a specified (or assumed) serving of that food, based primarily on US Department of Agriculture publications.¹ Individual nutrient intakes were estimated with and without taking supplement use into consideration, and two values were provided. Because the number of nutrients in the output varied over time (from 104 to 254 nutrients from 2005 to 2014), a total of 139 nutrients with <40% missing rate was included in this study. Cohort members with extremely low or high total caloric intake were excluded.⁴ None of our participants were removed due to having >70 missing items on the FFQ. A total of 1,829 Lovelace Smokers cohort and 508 Veteran Smokers cohort members completed the FFQ that passed the quality check. A convenient set of 28 cohort members completed an FFQ for a second time at follow-up visitŝ9.4 years after the study entry. Spearman correlation analysis was conducted for 102 nutrients with no missing data for these 28 cohort members to assess the stability of the dietary pattern over time.

Table S1 Nutrients associated with FEV₁/FVC ratio (%) in the LSC and VSCa

Table S2 The association between long chain unsaturated fatty acid and FEV₁/FVC decline (%) in the LSC (n=1,499)a

References

• RimmEBGiovannucciELStampferMJColditzGALitinLBWillettWCReproducibility and validity of an expanded self- administered semiquantitative food frequency questionnaire among male health professionalsAm J Epidemiol19921351011141126 Discussion 1127–11361632423
   PubMed Web of Science ®Google Scholar
• Pareo-TubbehSLRomeroLJBaumgartnerRNGarryPJLindemanRDKoehlerKMComparison of energy and nutrient sources of elderly Hispanics and non-Hispanic whites in New MexicoJ Am Diet Assoc199999557258210333779
   PubMedGoogle Scholar
• LindemanRDRomeroLJKoehlerKMSerum vitamin B12, C and folate concentrations in the New Mexico elder health survey: correlations with cognitive and affective functionsJ Am Coll Nutr2000191687610682878
   PubMed Web of Science ®Google Scholar
• StidleyCAPicchiMALengSMultivitamins, folate, and green vegetables protect against gene promoter methylation in the aerodigestive tract of smokersCancer Res201070256857420068159
   PubMed Web of Science ®Google Scholar

Acknowledgments

We thank Ms Laura Sampson, MS RD, at Harvard School of Public Health for assisting result interpretation. We thank Ms Xiequn Zhang, MS, at Lovelace Respiratory Research Institute for processing dietary data. We thank Ms Elise Calvillo for scientific editing of the figures. We thank the staff from Lovelace Scientific Resources for recruiting and enrolling study subjects and collecting lung function data. We thank the NM residents who participated in this study. This research was supported by NCI grant R01 CA097356, the State of New Mexico, as a direct appropriation from the Tobacco Settlement Fund and NIH/NCI P30 CA118100.

Disclosure

The authors report no financial and nonfinancial competing interests in this work.