Table 1.
Baseline Characteristics and Average 4-Year Lifestyle Changes among 120,877 U.S. Women and Men in Three Prospective Cohorts.*
| Variable | Nurses’ Health Study (N = 50,422 women) | Nurses’ Health Study II (N = 47,898 women) | Health Professionals Follow-up Study (N = 22,557 men) | |||
|---|---|---|---|---|---|---|
| Baseline | Change within Each 4-Year Period (5th–95th percentile)† | Baseline | Change within Each 4-Year Period (5th–95th percentile)† | Baseline | Change within Each 4-Year Period (5th–95th percentile)† | |
| Age — yr | 52.2±7.2 | 37.5±4.1 | 50.8±7.5 | |||
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| Weight — lb | 141±20 | 2.33 (−5.5 to 10.7)‡ | 138±20 | 5.24 (−2.3 to 16.3)‡ | 175±20 | 1.63 (−5.0 to 8.0)‡ |
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| Body-mass index | 23.7±1.4 | 0.40 (−0.94 to 1.83) | 23.0±2.7 | 0.69 (−1.05 to 2.82) | 24.7±1.1 | 0.24 (−0.70 to 1.20) |
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| Physical activity — MET-hr/wk§ | 14.8±9.9 | 1.78 (−9.24 to 15.3) | 21.6±25.9 | 0.53 (−12.6 to 14.7) | 22.9±15.1 | 6.7 (−8.90 to 33.6) |
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| Alcohol — drinks/day | 0.52±0.41 | −0.02 (−0.35 to 0.22) | 0.30±0.52 | 0.04 (−0.14 to 0.33) | 0.87±0.60 | 0.00 (−0.45 to 0.43) |
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| Total daily sleep — hr¶ | 7.0±0.5 | — | 7.0±1.0 | — | 7.1±0.5 | — |
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| Dietary intake — servings/day
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| Fruits | 1.6±0.6 | −0.10 (−0.96 to 0.59) | 1.2±0.9 | 0.03 (−0.48 to 0.57) | 1.5±0.6 | 0.05 (−0.57 to 0.72) |
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| Vegetables | 3.9±1.0 | −0.45 (−2.32 to 0.78) | 3.3±1.9 | 0.19 (−0.84 to 1.41) | 3.3±0.9 | 0.02 (−1.15 to 1.07) |
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| Whole-fat dairy foods | 1.2±0.5 | −0.16 (−0.86 to 0.36) | 0.8±0.7 | −0.02 (−0.45 to 0.50) | 0.9±0.5 | −0.09 (−0.64 to 0.36) |
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| Low-fat dairy foods | 0.9±0.5 | 0.11 (−0.46 to 0.83) | 1.1±0.9 | 0.02 (−0.59 to 0.64) | 0.8±0.5 | −0.05 (−0.64 to 0.43) |
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| Potato chips | 0.1±0.1 | −0.01 (−0.09 to 0.07) | 0.2±0.2 | −0.01 (−0.12 to 0.10) | 0.2±0.1 | −0.01 (−0.11 to 0.09) |
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| Potatoes | 0.4±0.1 | −0.01 (−0.19 to 0.18) | 0.4±0.3 | −0.02 (−0.17 to 0.12) | 0.4±0.1 | −0.01 (−0.18 to 0.18) |
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| Whole grains | 0.5±0.2 | 0.12 (−0.22 to 0.53) | 0.7±0.5 | 0.10 (−0.23 to 0.49) | 0.7±0.3 | 0.10 (−0.23 to 0.52) |
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| Refined grains | 1.2±0.4 | −0.03 (−0.60 to 0.57) | 1.3±0.8 | −0.09 (−0.67 to 0.40) | 1.2±0.5 | −0.01 (−0.57 to 0.56) |
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| Nuts | 0.2±0.1 | 0.01 (−0.15 to 0.20) | 0.1±0.1 | 0.06 (−0.05 to 0.33) | 0.2±0.2 | 0.02 (−0.22 to 0.29) |
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| Sugar-sweetened beverages | 0.2±0.2 | −0.00 (−0.14 to 0.11) | 0.3±0.6 | −0.03 (−0.31 to 0.14) | 0.3±0.3 | −0.02 (−0.22 to 0.14) |
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| Diet soda, 0 calories | 0.5±0.4 | −0.01 (−0.40 to 0.38) | 1.0±1.3 | −0.06 (−0.73 to 0.52) | 0.5±0.5 | 0.00 (−0.35 to 0.36) |
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| 100%-fruit juice | 0.8±0.4 | 0.06 (−0.43 to 0.64) | 0.6±0.7 | −0.03 (−0.45 to 0.33) | 0.8±0.4 | 0.01 (−0.44 to 0.50) |
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| Sweets and desserts | 1.3±0.6 | −0.01 (−0.75 to 0.75) | 1.3±1.1 | −0.06 (−0.65 to 0.45) | 1.5±0.7 | −0.03 (−0.76 to 0.70) |
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| Processed meats | 0.3±0.1 | −0.04 (−0.22 to 0.11) | 0.2±0.2 | 0.01 (−0.14 to 0.19) | 0.4±0.2 | −0.02 (−0.22 to 0.17) |
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| Unprocessed red meats | 0.6±0.2 | −0.06 (−0.32 to 0.14) | 0.6±0.4 | −0.01 (−0.24 to 0.21) | 0.6±0.2 | 0.02 (−0.28 to 0.41) |
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| Time spent watching television — hr/wk|| | 4.2±0.7 | — | 8.4±7.5 | 0.25 (−5.00 to 6.08) | 10.5±4.0 | −0.29 (−5.50 to 5.00) |
Plus–minus values are means ±SD. Data are based on 20 years of follow-up (1986–2006) in the Nurses’ Health Study (NHS), 12 years of follow-up (1991–2003) in the Nurses’ Health Study II (NHS II), and 20 years of follow-up (1986–2006) in the Health Professionals Follow-up Study (HPFS). Usual dietary habits and alcohol use were assessed every 4 years with the use of validated, semiquantitative food-frequency questionnaires. Alcohol included wine (5 oz), beer (1 glass, bottle, or can), and liquor (1 drink or shot). Other specific foods and beverages in each category are listed in Table 1 in the Supplementary Appendix. Results for smoking habits (assessed with the use of biennial questionnaires), trans fat, and fried foods can be found in Table 2 in the Supplementary Appendix. To convert pounds to kilograms, divide by 0.45.
Because serial assessments were limited, the 4-year changes could not be reliably quantified, and absolute levels at baseline were used for cohort-specific analyses.
The corresponding values for relative weight changes were 1.83% (5th to 95th percentile, −4.0 to 7.7) in the NHS, 3.60% (5th to 95th percentile, −1.80 to 10.7) in the NHS II, and 1.00% (5th to 95th percentile, −3.11 to 5.09) in the HPFS.
Physical activity was assessed by means of validated questionnaires every 2 years, with average energy expenditure (metabolic-equivalent [MET]-hours per week) for specific activities (e.g., walking, jogging, bicycling, swimming, racquet sports, and gardening). In the NHS II, physical activity levels in 1997, 2001, and 2005 were used to impute the levels in 1995, 1999, and 2003, respectively.
The average duration of sleep per 24-hour period was assessed in 1986, 2000, and 2002 in the NHS; in 2001 in the NHS II; and in 1987 and 2000 in the HPFS.
The average number of hours per week spent watching television at home was assessed in 1992 and 2004 in the NHS; in 1991, 1997, and 2001 in the NHS II; and in 1998 and every 2 years thereafter in the HPFS.