2Department of Internal Medicine, Narahigashi Hospital, Tenri, Nara, Japan 470 Nakanosho-cho, Tenri, Nara 632- 0001, Japan
Design: A cross-sectional study provided data from 508 male workers, aged 25 to 63 years. Participants completed a 58-item brieftype, self-administered dietary history questionnaire. The AHA-HD score include 8 components (fruits and vegetables, fish, whole grains, salt, sugar-sweetened beverages, processed meat, legumes, and saturated fatty acids).
Results: The AHA-HD score of all subjects ranged from 0 to 7; no participant had a full score for all 8 components. The prevalence of metabolic syndrome was significantly lower in subjects with high adherence to AHA-HD (met ≥4 components) than in those with low adherence (21.8% vs. 30.1%, respectively). High adherence to the AHA-HD was significantly associated with a low prevalence of metabolic syndrome (OR, 0.64; 95%CI, 0.42-0.97; p=0.038) after adjustment for age, total energy intake, smoking habit, and alcohol drinking.
Conclusions: Improving adherence to the AHA-HD recommendations may be an effective approach to promoting better health. Achievement of eating behaviors that meet ≥4 components of the AHA-HD may lead to a reduction in the risk for metabolic syndrome.
Key words: American Heart Association-recommended healthy diet; Japan; metabolic syndrome; workers;
Without metabolic syndrome |
With metabolic syndrome |
p |
|
N |
372 |
136 |
|
Age (years) |
45.2 ± 7.3 |
46.6 ± 6.4 |
0.042 |
Body weight (kg) |
62.9 ± 10.7 |
77.4 ± 10.7 |
0.001 |
BMI (kg/m2) |
23.7 ± 3.8 |
26.1 ± 2.5 |
0.001 |
Smoking (%) |
23.9 |
28.7 |
0.276 |
Moderate alcohol (%) |
20.4 |
16.9 |
0.376 |
Physically active (%) |
47.8 |
25.7 |
0.001 |
Waist (cm) |
84.1± 9.0 |
91.7 ± 6.1 |
0.001 |
SBP (mmHg) |
127 ± 16 |
140 ± 15 |
0.001 |
DBP (mmHg) |
78 ± 12 |
88 ± 10 |
0.001 |
Triglycerides (mg/dL) |
109 ± 65 |
194 ± 85 |
0.001 |
HDL-cholesterol (mg/dL) |
60 ± 13 |
51 ± 12 |
0.001 |
Fasting glucose (mg/dL) |
92 ± 10 |
102 ± 22 |
0.001 |
Total energy intake (kcal) |
1979 ± 550 |
1878 ± 535 |
0.067 |
Protein (%E) |
14.0 ± 2.5 |
13.6 ± 2.4 |
0.065 |
Fat (%E) |
25.2 ± 5.5 |
24.0 ± 5.3 |
0.034 |
Carbohydrate (%E) |
54.0 ± 8.0 |
54.6 ± 8.6 |
0.458 |
BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; HDL, high-density lipoprotein.
Number of Components |
All subjects |
Without metabolic syndrome |
With metabolic syndrome |
0 |
11 (2.2%) |
10 (2.7) |
1 (0.7) |
1 |
51 (10.0) |
32 (8.6) |
19 (14.0) |
2 |
101 (19.9) |
75 (20.2) |
26 (19.1) |
3 |
143 (28.1) |
97 (26.1) |
46 (33.8) |
4 |
117 (23.6) |
91 (24.5) |
26 (19.1) |
5 |
62 (12.2) |
49 (13.2) |
13 (9.6) |
6 |
18 (3.5) |
14 (3.8) |
4 (2.9) |
7 |
5 (1.0) |
4 (1.1) |
1 (0.7) |
8 |
0 (0) |
0 (0) |
0 (0) |
AHA-HDS, American Heart Association-recommended healthy diet score.
All subjects |
Without metabolic syndrome |
With metabolic syndrome |
pa |
|
Fruits and vegetables ≥400 g/day |
46.3 |
47.3 |
43.4 |
0.433 |
Fish ≥2 times/week* |
47.2 |
47.3 |
47.1 |
0.960 |
Fiber/carbohydrate ≥0.1 |
10.8 |
12.1 |
7.4 |
0.128 |
Salt <8 g/day |
0.8 |
0.5 |
1.5 |
0.293 |
Sugar sweetened beverages <2 times/week |
52.0 |
55.6 |
41.9 |
0.006 |
Processed meat <2 times/week |
60.2 |
59.4 |
62.5 |
0.529 |
Legumes ≥4 times/week |
35.0 |
36.8 |
30.1 |
0.163 |
Saturated fatty acid <7% of total energy |
63.2 |
61.8 |
66.9 |
0.294 |
a P values indicate difference between subjects with and without metabolic syndrome.
* At least 1 oily fish.
Components |
Low adherence to AHA-HD (0-3 components) |
High adherence to AHA-HD (4-8 components) |
P |
Metabolic syndrome |
30.1% |
21.80% |
0.039 |
Abdominal obesity |
35.9 |
25.3 |
0.013 |
High blood pressure |
54.2 |
55.0 |
0.877 |
High triglycerides |
38.2 |
29.2 |
0.036 |
Low HDL cholesterol |
9.5 |
2.5 |
0.002 |
High fasting glucose |
21.9 |
26.7 |
0.211 |
AHA-HDS, American Heart Association-recommended healthy diet score.
Model |
Odds ratio |
95% CI |
p |
Crude |
0.65 |
0.43 – 0.98 |
0.040 |
Model 1 |
0.61 |
0.40 – 0.93 |
0.020 |
Model 2 |
0.64 |
0.42 – 0.97 |
0.038 |
Model 3 |
0.67 |
0.44 – 1.04 |
0.075 |
Model 2: adjusted for age (years), total energy intake (kcal/day), smoking (yes, no), alcohol drinking (low, moderate, high).
Model 3: adjusted for model 2 components plus physically active (yes, no).
CI, confidence interval.
Adherence to this optimal diet was low in persons with metabolic syndrome. Several studies reported the prevalence of metabolic syndrome among various working populations, and these populations are often considered to have unhealthy eating habits [28]. Our results suggest that a healthy diet should be encouraged, especially in a working population. In addition, we found that an achievement of eating behaviors of ≥4 components of the AHA-HD was associated with a lower risk for metabolic syndrome.
This study has some limitations. First, among the AHA-HD components, we modified some cutoffs or assessment tools from the original AHA-HD definitions. For example, the cutoff of salt intake was amended to correct upwards (< 8 g per day), as described in the Methods section. The BDHQ used in this study is not designed to evaluate the total amount of whole grains, and therefore, whole grain intake was transformed to the ratio of dietary fiber to carbohydrate (≥0.1 in this study). This definition comes from a report from the Harvard School of Public Health [13]. The Harvard researchers evaluated 545 grain products to find the best way to identify a healthful whole grain food: food that met the 10:1 ratio that tends to match unprocessed wheat [13]. The assessment for fruits and vegetables was also modified from the original AHA-HD definition (≥4.5 servings per day) to the surrogate definition (≥400 g per day), because use of serving units for fruits and vegetables is not common in Japan. Second, the lack of a randomly selected sample could lead to selection bias. Additional investigations including subjects with a wider range of occupations are needed. Third, education level, family income of participants, job stress, and the presence of shift work might contribute to adherence to a healthy diet, but we did not have such information. Finally, as a cross-sectional study, the present results cannot prove a causal relationship between the AHA-HD adherence and the risk reduction for metabolic syndrome. In addition, the independent effect of high adherence to AHA-HD was attenuated by the fully adjusted model (by adding physical activity as a confounding factor). Although it is commonly said that both physical activity and healthy dietary habits may contribute to a lower risk for metabolic syndrome [29], it is controversial whether physical activity or a healthier diet is more closely related to risk reduction of metabolic syndrome.
Despite these limitations, the main strength of our study was that we collected detailed data on dietary intakes and we could apply all 8 components of the AHA-HD. In recent decades, Japan has been replacing the traditional Japanese diet with an American-style diet or with other less healthy eating habits. This study adds new information regarding the lack of ideal healthy dietary status in contemporary Japan, and in particular, male workers.
In conclusion, the prevalence of metabolic syndrome was significantly lower in subjects with high adherence to AHAHD (met ≥4 components) than in those with low adherence (21.8% vs. 30.1%, respectively). High adherence to the AHA-HD was significantly associated with a low prevalence of metabolic syndrome (OR, 0.64; 95%CI, 0.42-0.97; p=0.038) after adjustment for age, total energy intake, smoking habit, and alcohol drinking. Improvement of adherence to the AHA-HD may be an effective approach to promoting better health and reducing the risk for metabolic syndrome.
b. Ethical Approval: This study was approved by the Institutional Review Board of Kio University.
c. Clinical trial registration: This was an observational study. Written informed consent was obtained from each participant.
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