Mediterranean diet and hip fracture incidence among older adults: the CHANCES project

The association between adherence to Mediterranean diet (MD) and hip fracture incidence is not yet established. In a diverse population of elderly, increased adherence to MD was associated with lower hip fracture incidence. Except preventing major chronic diseases, adhering to MD might have additional benefits in lowering hip fracture risk.

INTRODUCTION

Hip fractures constitute a major public health problem among older adults. Latest evidence links adherence to Mediterranean diet (MD) with reduced hip fracture risk, but still more research is needed to elucidate this relationship. The potential association of adherence to MD with hip fracture incidence was explored among older adults.

METHODS

A total of 140,775 adults (116,176 women, 24,599 men) 60 years and older, from five cohorts from Europe and the USA, were followed-up for 1,896,219 person-years experiencing 5454 hip fractures. Diet was assessed at baseline by validated, cohort-specific, food-frequency questionnaires, and hip fractures were ascertained through patient registers or telephone interviews/questionnaires. Adherence to MD was evaluated by a scoring system on a 10-point scale modified to be applied also to non-Mediterranean populations. In order to evaluate the association between MD and hip fracture incidence, cohort-specific hazard ratios (HR), adjusted for potential confounders, were estimated using Cox proportional-hazards regression and pooled estimates were subsequently derived implementing random-effects meta-analysis.

RESULTS

A two-point increase in the score was associated with a significant 4% decrease in hip fracture risk (pooled adjusted HR 0.96; 95% confidence interval (95% CI) 0.92-0.99, p_{heterogeneity} = 0.446). In categorical analyses, hip fracture risk was lower among men and women with moderate (HR 0.93; 95% CI 0.87-0.99) and high (HR 0.94; 95% CI 0.87-1.01) adherence to the score compared with those with low adherence.

CONCLUSIONS

In this large sample of older adults from Europe and the USA, increased adherence to MD was associated with lower hip fracture incidence.

Milk and other dairy foods and risk of hip fracture in men and women

The role of dairy foods for hip fracture prevention remains controversial. In this study, among US men and women, a glass of milk per day was associated with an 8% lower risk of hip fracture. This contrasts with a reported increased risk with higher milk intake in Swedish women.

INTRODUCTION

The purpose of this study was to examine whether higher milk and dairy food consumption are associated with risk of hip fracture in older adults following a report of an increased risk for milk in Swedish women.

METHODS

In two US cohorts, 80,600 postmenopausal women and 43,306 men over 50 years of age were followed for up to 32 years. Cox proportional hazards models were used to calculate the relative risks (RR) of hip fracture per daily serving of milk (240 mL) and other dairy foods that were assessed every 4 years, controlling for other dietary intakes, BMI, height, smoking, activity, medications, and disease diagnoses.

RESULTS

Two thousand one hundred thirty-eight incident hip fractures were identified in women and 694 in men. Each serving of milk per day was associated with a significant 8% lower risk of hip fracture in men and women combined (RR = 0.92, 95% confidence interval (CI) 0.87 to 0.97). A suggestive inverse association was found for cheese in women only (RR = 0.91, CI 0.81 to 1.02). Yogurt consumption was low and not associated with risk. Total dairy food intake, of which milk contributed about half, was associated with a significant 6% lower risk of hip fracture per daily serving in men and women (RR = 0.94, CI 0.90 to 0.98). Calcium, vitamin D, and protein from non-dairy sources did not modify the association between milk and hip fracture, nor was it explained by contributions of these nutrients from milk.

CONCLUSIONS

In this group of older US adults, higher milk consumption was associated with a lower risk of hip fracture.

Multivitamin use and risk of stroke incidence and mortality amongst women

BACKGROUND AND PURPOSE

Few studies have examined the association between multivitamin use and the risk of stroke incidence and mortality, and the results remain inconclusive as to whether multivitamins are beneficial.

METHODS

The associations between multivitamin use and the risk of incident stroke and stroke mortality were prospectively examined in 86 142 women in the Nurses' Health Study, aged 34-59 years and free of diagnosed cardiovascular disease at baseline. Multivitamin use and covariates were updated every 2 years and strokes were documented by review of medical records. Hazard ratios of total, ischaemic and hemorrhagic strokes were calculated across categories of multivitamin use (non-user, past, current user) and duration (years), using Cox proportional hazards models.

RESULTS

During 32 years of follow-up from 1980 to 2012, 3615 incident strokes were documented, including 758 deaths from stroke. In multivariate analyses, women who were current multivitamin users did not have a lower risk of incident total stroke compared to non-users [relative risk (RR) 1.02, 95% confidence interval (CI) 0.93-1.11], even those with longer durations of 15 or more years of use (RR 1.08, 95% CI 0.97-1.20) or those with a lower quality diet (RR 0.96, 95% CI 0.80-1.15). There was also no indication of benefit from multivitamin use for incident ischaemic or hemorrhagic strokes or for total stroke mortality.

CONCLUSIONS

Long-term multivitamin use was not associated with reduced risk of stroke incidence or mortality amongst women in the study population, even amongst those with a lower diet quality. An effect in a less well-nourished population cannot be ruled out.

Protein intake and risk of hip fractures in postmenopausal women and men age 50 and older

In this study, we followed postmenopausal women and men aged 50 and above for up to 32 years and found no evidence that higher protein intake increased the risk of hip fracture. Protein intake from specific sources was inversely associated with risk, but these associations appeared to differ by gender.

INTRODUCTION

We examined the association between intakes of total and specific sources of protein and hip fracture risk in postmenopausal women and men over 50 years of age. Our hypothesis was that a higher protein intake would not be associated with a higher risk of hip fractures.

METHODS

In this analysis, we followed 74,443 women in the Nurses' Health Study between 1980 and 2012 and 35,439 men from the Health Professionals Follow-up Study between 1986 and 2012. Health and lifestyle information and hip fractures were self-reported on biennial questionnaires. Protein was assessed approximately every 4 years with a food frequency questionnaire. Relative risks (RR) were computed for hip fracture by quintiles of total, animal, dairy, and plant protein intakes using Cox proportional hazard models, adjusting for potential confounders.

RESULTS

During follow-up, we ascertained 2156 incident hip fractures in women and 595 fractures in men. Among men, we observed significant inverse associations for each 10 g increase of total protein (RR = 0.92, 95% CI = 0.85-0.99) and animal protein (RR = 0.91, 95% CI = 0.85-0.98) intakes. Total and animal proteins were not significantly associated with hip fractures in women. Both plant (RR = 0.88, 95% CI 0.79-0.99 per 10 g) and dairy protein (RR = 0.92, 95% CI 0.86-0.97) were associated with significantly lower risks of hip fracture when results for men and women were combined. None of these associations were modified by BMI, smoking, physical activity, age, or calcium intake.

CONCLUSION

We found no evidence that higher protein intake increases risk of hip fracture in these Caucasian men and women. Protein intake from specific sources was inversely associated with risk, but these associations appeared to differ by gender.

Excess mortality after hip fracture in elderly persons from Europe and the USA: the CHANCES project

BACKGROUND

Hip fractures are associated with diminished quality of life and survival especially amongst the elderly.

OBJECTIVE

All-cause mortality after hip fracture was investigated to assess its magnitude.

METHODS

A total of 122 808 participants from eight cohorts in Europe and the USA were followed up for a mean of 12.6 years, accumulating 4273 incident hip fractures and 27 999 deaths. Incident hip fractures were assessed through telephone interviews/questionnaires or national inpatient/fracture registries, and causes of death were verified with death certificates. Cox proportional hazards models and the time-dependent variable methodology were used to assess the association between hip fracture and mortality and its magnitude at different time intervals after the injury in each cohort. We obtained the effect estimates through a random-effects meta-analysis.

RESULTS

Hip fracture was positively associated with increased all-cause mortality; the hazard ratio (HR) in the fully adjusted model was 2.12, 95% confidence interval (CI) 1.76-2.57, after adjusting for potential confounders. This association was stronger amongst men [HR: 2.39, 95% CI: 1.72-3.31] than amongst women [HR: 1.92, 95% CI: 1.54-2.39], although this difference was not significant. Mortality was higher during the first year after the hip fracture [HR: 2.78, 95% CI: 2.12-3.64], but it remained elevated without major fluctuations after longer time since hip fracture [HR (95% CI): 1.89 (1.50-2.37) after 1-4 years; 2.15 (1.81-2.55) after 4-8 years; 1.79 (1.57-2.05) after 8 or more years].

CONCLUSION

In this large population-based sample of older persons across eight cohorts, hip fracture was associated with excess short- and long-term all-cause mortality in both sexes.

Abdominal obesity and hip fracture: results from the Nurses' Health Study and the Health Professionals Follow-up Study

Abdominal obesity might increase fracture risk. We studied the prospective associations between waist circumference, waist-to-hip ratio, and hip fracture. The indicators of abdominal obesity were associated with increased hip fracture risk in women, but not in men. The increased risk was restricted to women with low physical activity.

INTRODUCTION

Low weight is an established risk factor for osteoporosis and hip fracture. However, the association between fat tissue, muscle, and bone is complex, and abdominal obesity might increase fracture risk. We studied the prospective associations between indicators of abdominal obesity and hip fracture in two large US cohorts.

METHODS

At baseline in 1986 and through biennial follow-up, information on hip fracture and potential risk factors was collected in 61,677 postmenopausal women and 35,488 men above age 50. Waist and hip circumferences were reported at baseline and updated twice.

RESULTS

During follow-up, 1168 women and 483 men sustained a hip fracture. After controlling for known risk factors, there was a significant association in women between increasing waist circumference and hip fracture (RR per 10-cm increase 1.13 (95 % CI 1.04-1.23) and between increasing waist-to-hip ratio and hip fracture (RR per 0.1 unit increase 1.14 (95 % CI 1.04-1.23), but these associations were not seen in men. In women, both measures interacted with physical activity. Those in the highest (≥0.90) versus lowest (<0.75) category of waist-to-hip ratio had increased risk of hip fracture if their activity was less than the population median (RR = 1.61, 95 % CI 1.18-2.19) but not if their activity was higher (RR = 1.00, 95 % CI 0.72-1.40). A similar pattern was found for waist circumference.

CONCLUSION

Indicators of abdominal obesity were associated with increased hip fracture risk after controlling for BMI in women. The increased risk was restricted to women with low physical activity. In men, no significant associations were found.

Education, marital status, and risk of hip fractures in older men and women: the CHANCES project

The role of socioeconomic status in hip fracture incidence is unclear. In a diverse population of elderly, higher education was found to be associated with lower, whereas living alone, compared to being married/cohabiting, with higher hip fracture risk. Educational level and marital status may contribute to hip fracture risk.

INTRODUCTION

The evidence on the association between socioeconomic status and hip fracture incidence is limited and inconsistent. We investigated the potential association of education and marital status with hip fracture incidence in older individuals from Europe and USA.

METHODS

A total of 155,940 participants (79 % women) aged 60 years and older from seven cohorts were followed up accumulating 6456 incident hip fractures. Information on education and marital status was harmonized across cohorts. Hip fractures were ascertained through telephone interviews/questionnaires or through record linkage with registries. Associations were assessed through Cox proportional hazard regression adjusting for several factors. Summary estimates were derived using random effects models.

RESULTS

Individuals with higher education, compared to those with low education, had lower hip fracture risk [hazard ratio (HR) = 0.84, 95 % confidence interval (CI) 0.72-0.95]. Respective HRs were 0.97 (95 % CI 0.82-1.13) for men and 0.75 (95 % CI 0.65-0.85) for women. Overall, individuals living alone, especially those aged 60-69 years, compared to those being married/cohabiting, tended to have a higher hip fracture risk (HR = 1.12, 95 % CI 1.02-1.22). There was no suggestion for heterogeneity across cohorts (P heterogeneity > 0.05).

CONCLUSIONS

The combined data from >150,000 individuals 60 years and older suggest that higher education may contribute to lower hip fracture risk. Furthermore, this risk may be higher among individuals living alone, especially among the age group 60-69 years, when compared to those being married/cohabiting.

Dietary patterns and risk of hip fractures in postmenopausal women and men over 50 years

We followed 74,540 postmenopausal women and 35,451 men above age 50 for up to 30 years. Neither the prudent pattern, characterized by higher intakes of whole grains, fruits, and vegetables, nor the Western pattern, characterized by higher intakes of red/processed meats, and refined grains were associated with hip fracture risk.

INTRODUCTION

We examined the association between predominant dietary patterns and risk of hip fractures in postmenopausal women and men over 50 years.

METHODS

We used data from 74,540 women in the Nurses' Health Study followed between 1980 and 2010, and 35,451 men from the Health Professionals Follow-up Study followed between 1986 and 2012 for this analysis. Health and lifestyle information was assessed every 2 years. Diet was assessed approximately every 4 years with a food frequency questionnaire. Two major dietary patterns were previously derived using principal component analysis. The prudent pattern is characterized by higher intakes of fruits, vegetables, whole grains, and poultry, and the Western pattern is characterized by higher intakes of red and processed meats, sweets, and refined grains. We computed relative risks (RR) for hip fracture by dietary pattern scores using Cox proportional hazards models, adjusting for potential confounders.

RESULTS

During follow-up, there were 1891 hip fractures in women and 596 in men. No association was observed between the prudent or Western pattern and risk of hip fractures in either men or women. We also did not find an association among lean (body mass index (BMI) <25) or overweight (BMI ≥25) individuals or among those with higher or lower levels of physical activity.

CONCLUSION

Neither the prudent nor the Western dietary pattern was associated with risk of hip fractures in postmenopausal women or men over 50 years of age.

Dietary intake of polyunsaturated fatty acids and risk of hip fracture in men and women

Data on the impact of polyunsaturated fatty acid intake on hip fracture risk are inconsistent. We investigated this association in 75,878 women and 46,476 men and did not find a significant role for polyunsaturated fatty acid intake in the prevention of hip fractures.

INTRODUCTION

Polyunsaturated fatty acids (PUFA) are important in the prevention of chronic diseases, but studies of bone health report inconsistent results. Our aim was to investigate the association between dietary PUFA intake and risk of hip fracture in two large prospective cohorts of men and women with long follow-up times and frequently updated dietary data.

METHODS

The study population included 75,878 women and 46,476 men free of osteoporosis at baseline. Dietary intakes were assessed by a food frequency questionnaire at baseline and several times during the follow-up. Multivariable-adjusted Cox proportional hazards models were used to estimate relative risks (RR).

RESULTS

During 24 years of follow-up, we identified 1,051 hip fracture cases due to low or moderate trauma among the women and 529 cases among the men. In the pooled analyses, no statistically significant associations were found between intakes of total PUFA [RR in the highest vs. lowest quintile: 0.99, 95% confidence interval (CI) 0.69, 1.43; p value for trend is =0.83], total n-3 PUFA (RR 0.89, 95% CI 0.75, 1.06; p value for trend is =0.26), total n-6 PUFA (RR 0.99, 95% CI 0.71, 1.38; p value for trend is =0.82), n-6/n-3 PUFA ratio or individual PUFAs, and hip fracture risk. However, in women low intakes of total PUFA, total n-6 PUFA, and linoleic acid were associated with higher risk.

CONCLUSIONS

This study does not support a significant role for PUFA intake in the prevention of hip fractures, although low total PUFA, n-6 PUFA, or linoleic acid intakes may increase the risk in women.

Physical activity patterns and prevention of weight gain in premenopausal women

BACKGROUND

Studies of the association between physical activity (PA) and weight maintenance have been inconsistent.

METHODS

We prospectively examined the association between PA patterns and prevention of weight gain among 46,754 healthy premenopausal women, aged 25–43 years in 1989. Participants reported their PA and weight in 1989 and 1997. The primary outcome was gaining >5% of baseline weight by 1997 (62% of the population).

RESULTS

Compared with women who maintained <30 minutes/day of total discretionary activity over 8 years, women were less likely to gain weight if they sustained 30+ minutes/day (Odds Ratio OR=0.68, 95% confidence interval [CI] 0.64–0.73) or increased to 30+ minutes/day in 1997 (OR=0.64, 95%CI=0.60–0.68). Among women whose only reported activity was walking, risk of gaining weight was lower in those who sustained 30+ minutes/day over 8 years (OR=0.66, 95%CI=0.49–0.91), and brisk walking pace independently predicted less weight gain. For a 30 minutes/day increase between 1989 and 1997, jogging/running was associated with less weight gain than brisk walking or other activities. Greater duration of PA was associated with progressively less weight gain, but even an 11–20 minutes/day increase was beneficial; the benefits appeared stronger among those initially overweight. Sedentary behavior independently predicted weight gain.

CONCLUSIONS

Sustained PA for at least 30 minutes/day, particularly if more intense, is associated with a reduction in long-term weight gain, and greater duration is associated with less weight gain. Sedentary women of any baseline weight who increase their PA will benefit, but overweight women appear to benefit the most.

A prospective study of reproductive factors, hormone use, and risk of lung cancer in postmenopausal women

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Background: There has been increased interest in understanding the role of hormonal factors in lung cancer (LC) in women with the observation that it exhibits different epidemiologic patterns and treatment response when compared to men. However, results of published studies have been inconsistent, possibly due to inadequate smoking adjustment. Methods: We prospectively examined the associations between reproductive factors, exogenous hormone use, and LC incidence in 106,574 postmenopausal women in the Nurses’ Health Study. Participants completed biennial questionnaires which included updated smoking history. We assessed age at menopause, age at menarche, type of menopause, parity, postmenopausal hormone (PMH), and oral contraceptive use. Cox proportional hazards modeling was used to estimate the relative risks (RR) of each exposure, adjusted for smoking status, number of cigarettes, time since quitting, age of initiating smoking, fruit/vegetable intake, body mass index, and environmental smoking exposure. Results: We identified 1,565 LC cases during follow up from 1984 to 2004. Parity was associated with decreased LC risk in never smokers (RR = 0.54, 95% CI 0.31–0.96) but increased risk in current smokers (RR = 1.44, 95% CI 1.03–2.02). No association was seen in former smokers. Also, younger age at menopause was associated with higher LC risk in women with natural menopause (p-trend = 0.016). PMH use was not associated with LC incidence. The RR for current PMH users was 1.01 (95% CI 0.87–1.17) and for past users was 0.95 (95% CI 0.82–1.1). No significant association was seen when assessed by duration of PMH use, time since last use, or type of PMH. However, past use of oral contraceptives for greater than 5 years was associated with increased LC risk (RR = 1.2, 95% CI 1.03–1.41). Conclusions: These results suggest that there may be an association between hormonal factors and LC development, and further suggest that the mechanism may differ in smokers versus lifelong never smokers.

No significant financial relationships to disclose.

Nightshift work and fracture risk: the Nurses' Health Study

SUMMARY

Nightshift work suppresses melatonin production and has been associated with an increased risk of major diseases including hormonally related tumors. Experimental evidence suggests that light at night acts through endocrine disruption likely mediated by melatonin. To date, no observational study has addressed the effect of night work on osteoporotic fractures, another condition highly sensitive to sex steroid exposure. Our study, to our knowledge, the first to address this question, supports the hypothesis that nightshift work may negatively affect bone health, adding to the growing list of ailments that have been associated with shift work.

INTRODUCTION

We evaluated the association between nightshift work and fractures at the hip and wrist in postmenopausal nurses.

METHODS

The study population was drawn from Nurses' Health Study participants who were working full or part time in nursing in 1988 and had reported their total number of years of rotating nightshift work. Through 2000, 1,223 incident wrist and hip fractures involving low or moderate trauma were identified among 38,062 postmenopausal women. We calculated multivariate relative risks (RR) of fracture over varying lengths of follow-up in relation to years of nightshift work.

RESULTS

Compared with women who never worked night shifts, 20+ years of nightshift work was associated with a significantly increased risk of wrist and hip fractures over 8 years of follow-up [RR = 1.37, 95% confidence interval (CI), 1.04-1.80]. This risk was strongest among women with a lower body mass index (<24) who never used hormone replacement therapy (RR = 2.36; 95% CI, 1.33-4.20). The elevated risk was no longer apparent with 12 years of follow-up after the baseline single assessment of nightshift work.

CONCLUSIONS

Long durations of rotating nightshift work may contribute to risk of hip and wrist fractures, although the potential for unexplained confounding cannot be ruled out.

Aspirin and lung cancer risk in a cohort study of women: dosage, duration and latency

Aspirin may reduce the risk of cancer at some sites but its effect at the lung is unclear. We prospectively examined associations between aspirin use and risk of lung cancer in 109,348 women in the Nurses' Health study from 1980 to 2004. During this time, 1,360 lung cancers were documented in participants 36-82 years of age. Aspirin use and smoking were assessed every 2 years. Risk of lung cancer was a non-significant 16% lower for regular aspirin users of one or two tablets per week and a significant 55% higher for users of 15 or more tablets per week compared with women who never regularly used aspirin. Results were similar when limited to never smokers. For both the low and high quantity aspirin users, risk of lung cancer did not decline or increase with longer durations of use, and associations attenuated as the latency period between aspirin assessment and lung cancer diagnosis was lengthened. Our findings, together with those from previous clinical trials and prospective studies, do not provide consistent evidence that aspirin influences the development of lung cancer and further investigation is required with adjustment for smoking.

Vitamin D intake and risks of systemic lupus erythematosus and rheumatoid arthritis in women

OBJECTIVES

Vitamin D has immune-modulating effects and may protect against the development of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

METHODS

We identified incident cases of SLE and RA among 186 389 women followed from 1980 to 2002 in the Nurses' Health Study and Nurses' Health Study II cohorts. We excluded subjects where SLE or RA was not confirmed by medical record review, and those who failed to return questionnaires. Semi-quantitative food frequency questionnaires assessed vitamin D intake from food and supplements. We used cumulative-updated total energy-adjusted dietary exposures for each 2-year cycle. Relationships between vitamin D intake and incident SLE and RA were examined in age-adjusted and Cox proportional hazards models, adjusted for confounders. Results were pooled using meta-analysis random effects models.

RESULTS

We confirmed 190 incident cases of SLE and 722 of RA with dietary information. Increasing levels of vitamin D intake had no relationship to the relative risk of developing either SLE or RA.

CONCLUSIONS

Vitamin D intake was not associated with risk of SLE or RA in these large prospective cohorts of women.

Physical activity and risk of breast cancer in premenopausal women

Physical activity appears to be inversely related to risk of breast cancer, yet the results remain inconsistent. To evaluate this relation among premenopausal women and examine variation in risk according to level of obesity and use of oral contraceptives (OCs), the authors examined data from the Nurses' Health Study II. During 10 years of follow-up, 849 cases of invasive premenopausal breast cancer were confirmed. Physical activity was assessed by self-report at baseline and during follow-up using a validated questionnaire. Total physical activity was unrelated to risk of breast cancer. Women engaging in >or=27 metabolic equivalent (MET)-h week(-1) had a multivariate-adjusted relative risk (RR) of 1.04 (95% confidence interval (CI) 0.82-1.33) compared to those in the <3 MET-h week(-1) category. Among women with a BMI >or=30 kg m(-2), we observed a significant positive dose-response relation (P=0.04). Activity was unrelated to breast cancer risk at lower levels of BMI. A test for interaction between activity and BMI (<30, >or=30 kg m(-2)) was statistically significant (P=0.02). Among current OC users, higher activity was associated with a non-significantly lower risk of breast cancer (RR=0.59, 95% CI 0.30-1.16 for >or=27 vs <9 MET-h week(-1), P for linear trend=0.14). These results show no overall association between physical activity and risk of breast cancer among premenopausal women, but suggest that the effect of physical activity could be substantially modified by the underlying degree of adiposity. The potential interactions between physical activity, adiposity, and current use of OCs require further study.

Dietary intakes of vitamins A, C, and E and risk of melanoma in two cohorts of women

Within the two Nurses' Health Study cohorts of US women, we examined whether higher intakes of vitamin C, vitamin E, retinol, or individual tocopherols or carotenoids are associated with a lower risk of melanoma. We confirmed 414 cases of invasive melanoma among over 162,000 Caucasian women aged 25-77 years during more than 1.6 million person-years of follow-up. Diet was measured every 4 years with a food frequency questionnaire and supplement use was reported every 2 years. Several measures of sun sensitivity were assessed and included in proportional hazards models. We found that vitamins A, C, E and their individual components were not associated with a lower risk of melanoma. Only retinol intake from foods plus supplements appeared protective within a subgroup of women who were otherwise at low risk based on nondietary factors (relative risk (RR)=0.39, 95% confidence interval (CI) 0.22-0.71 for >/=1,800 vs 400 microg day(-1), P for linear trend=0.01). Contrary to expectation, we observed higher risks of melanoma with greater intakes of vitamin C from food only (RR=1.43, 95% CI 1.01-2.00 for >/=175 vs <90 mg day(-1), P for linear trend=0.05) and a significant positive dose-response with frequency of orange juice consumption (P=0.008). Further research is needed to determine whether another component in foods such as orange juice may contribute to an increase in risk.

Stress and suicide in the Nurses' Health Study

STUDY OBJECTIVES

Although stress is thought to be a risk factor for suicide, most research has been retrospective or has focused on attempted suicides or suicide ideation. This study examined prospectively the associations between self perceived stress, diazepam use, and death from suicide among adult women.

DESIGN

A cohort study was conducted with 14 years of follow up. Stress at home and at work were assessed by questionnaire and scored on a four point scale: minimal, light, moderate, or severe.

SETTING

Eleven states within the United States.

PARTICIPANTS

Female nurses (n=94 110) who were 36 to 61 years of age when they answered questions on stress and diazepam use in 1982.

RESULTS

During 1 272 000 person years of observation 73 suicides were identified. After adjustment for age, smoking, coffee consumption, alcohol intake, and marital status, the relation between self reported stress and suicide remained U shaped. Compared with the light home and work stress categories, which had the lowest incidences of suicide, risks were increased among women reporting either severe (relative risk (RR) = 3.7, 95% confidence intervals (CI) 1.7 to 8.3) or minimal (RR=2.1, 95% CI 1.0 to 4.5) home stress and either severe (RR=1.9, 95% CI 0.8 to 4.7) or minimal (RR=2.4, 95% CI 0.9 to 6.1) work stress. When responses to home and work stress were combined, there was an almost fivefold increase in risk of suicide among women in the high stress category. Risk of suicide was over eightfold among women reporting high stress or diazepam use compared with those reporting low stress and no diazepam use.

CONCLUSIONS

The relation between self reported stress and suicide seems to be U shaped among adult women. The excess risk for those reporting minimal stress may reflect denial or undiagnosed depression or an association with some other unmeasured risk factor for suicide.

Prospective study of fruit and vegetable consumption and risk of lung cancer among men and women

BACKGROUND

Diets high in fruits and vegetables have been shown to be associated with a lower risk of lung cancer. beta-Carotene was hypothesized to be largely responsible for the apparent protective effect, but this hypothesis was not supported by clinical trials.

METHODS

We examined the association between lung cancer risk and fruit and vegetable consumption in 77 283 women in the Nurses' Health Study and 47 778 men in the Health Professionals' Follow-up Study. Diet was assessed with the use of a food-frequency questionnaire that included 15 fruits and 23 vegetables. We used logistic regression models to estimate relative risks (RRs) of lung cancer within each cohort. All statistical tests were two-sided.

RESULTS

We documented 519 lung cancer cases among the women and 274 among the men. Total fruit and vegetable consumption was associated with a modestly lower risk of lung cancer among the women but not among the men. The RR for the highest versus lowest quintile of intake was 0.79 (95% confidence interval [CI] = 0.59-1.06) among the women and 1.12 (95% CI = 0.74-1.69) among the men after adjustment for smoking status, quantity of cigarettes smoked per day, time since quitting smoking, and age at initiation of smoking. However, total fruit and vegetable consumption was associated with a lower risk of lung cancer among never smokers in the combined cohorts, although the reduction was not statistically significant (RR = 0.63; 95% CI = 0.35-1.12 in the highest tertile).

CONCLUSION

Higher fruit and vegetable intakes were associated with lower risks of lung cancer in women but not in men. It is possible that the inverse association among the women remained confounded by unmeasured smoking characteristics, although fruits and vegetables were protective in both men and women who never smoked.

Adherence to the Dietary Guidelines for Americans and risk of major chronic disease in men

BACKGROUND

The Dietary Guidelines for Americans and the food guide pyramid aim to reduce the risk of major chronic disease in the United States, but data supporting their overall effectiveness are sparse. The healthy eating index (HEI) measures the concordance of dietary patterns with these guidelines.

OBJECTIVE

We tested whether a high HEI score (range: 0-100; 100 is best) calculated from a validated food-frequency questionnaire (HEI-f) could predict lower risk of major chronic disease in men.

DESIGN

A cohort of US male health professionals without major disease completed detailed questionnaires on food intake and other risk factors for heart disease and cancer in 1986 and repeatedly during the 8-y follow-up. Major chronic disease outcome was defined as incident major cardiovascular disease (stroke or myocardial infarction, n = 1092), cancer (n = 1661), or other non-trauma-related deaths (n = 366).

RESULTS

The HEI-f was weakly inversely associated with risk of major chronic disease [comparing highest with lowest quintile of the HEI-f, relative risk (RR) = 0.89; 95% CI: 0.79, 1.00; P: < 0.001 for trend]. The HEI-f was associated with moderately lower risk of cardiovascular disease (RR = 0.72; 95% CI: 0.60, 0.88; P: < 0.001) but was not associated with lower cancer risk.

CONCLUSIONS

The HEI-f was only weakly associated with risk of major chronic disease, suggesting that improvements to the HEI may be warranted. Further research on the HEI could have implications for refinements to the Dietary Guidelines for Americans and the food guide pyramid.

Adherence to the Dietary Guidelines for Americans and risk of major chronic disease in women

BACKGROUND

Little is known about the overall health effects of adherence to the Dietary Guidelines for Americans. The healthy eating index (HEI), developed at the US Department of Agriculture, measures how well Americans' diets conform to these guidelines.

OBJECTIVE

We tested whether the HEI (scores range from 0 to 100; 100 is best) calculated from food-frequency questionnaires (HEI-f) would predict risk of major chronic disease in women.

DESIGN

A total of 67272 US female nurses who were free of major disease completed detailed questionnaires on diet and chronic disease risk factors in 1984 and repeatedly over 12 y. Major chronic disease was defined as fatal or nonfatal cardiovascular disease (myocardial infarction or stroke, n = 1365), fatal or nonfatal cancer (n = 5216), or other nontraumatic deaths (n = 496), whichever came first. We also examined cardiovascular disease and cancer as separate outcomes.

RESULTS

After adjustment for smoking and other risk factors, the HEI-f score was not associated with risk of overall major chronic disease in women [relative risk (RR) = 0.97; 95% CI: 0.89, 1.06 comparing the highest with the lowest quintile of HEI-f score]. Being in the highest HEI-f quintile was associated with a 14% reduction in cardiovascular disease risk (RR = 0.86; 95% CI: 0.72, 1. 03) and was not associated with lower cancer risk (RR = 1.02; 95% CI: 0.93, 1.12).

CONCLUSION

These data suggest that adherence to the 1995 Dietary Guidelines for Americans, as measured by the HEI-f, will have limited benefit in preventing major chronic disease in women.

Intake of specific carotenoids and risk of lung cancer in 2 prospective US cohorts

BACKGROUND

Carotenoids may reduce lung carcinogenesis because of their antioxidant properties; however, few studies have examined the relation between intakes of individual carotenoids and lung cancer risk.

OBJECTIVE

The aim of this study was to examine the relation between lung cancer risk and intakes of alpha-carotene, beta-carotene, lutein, lycopene, and beta-cryptoxanthin in 2 large cohorts.

DESIGN

During a 10-y follow-up period, 275 new cases of lung cancer were diagnosed in 46924 men; during a 12-y follow-up period, 519 new cases were diagnosed in 77283 women. Carotenoid intakes were derived from the reported consumption of fruit and vegetables on food-frequency questionnaires administered at baseline and during follow-up. The data were analyzed separately for each cohort and the results were pooled to compute overall relative risks (RRs).

RESULTS

In the pooled analyses, alpha-carotene and lycopene intakes were significantly associated with a lower risk of lung cancer; the association with beta-carotene, lutein, and beta-cryptoxanthin intakes were inverse but not significant. Lung cancer risk was significantly lower in subjects who consumed a diet high in a variety of carotenoids (RR: 0.68; 95% CI: 0.49, 0.94 for highest compared with lowest total carotenoid score category). Inverse associations were strongest after a 4-8-y lag between dietary assessment and date of diagnosis. In subjects who never smoked, a 63% lower incidence of lung cancer was observed for the top compared with the bottom quintile of alpha-carotene intake (RR: 0.37; 95% CI: 0.18, 0.77).

CONCLUSION

Data from 2 cohort studies suggest that several carotenoids may reduce the risk of lung cancer.

Oral contraceptive use and risk of melanoma in premenopausal women

Melanoma has been increasing in white populations. Incidence rates rise steeply in women until about age 50, suggesting oestrogen as a possible risk factor. Oestrogens can increase melanocyte count and melanin content and cause hyperpigmentation of the skin. We examined prospectively the association between oral contraceptive (OC) use and diagnoses of superficial spreading and nodular melanoma among 183,693 premenopausal white women in the Nurses' Health Study (NHS) and the Nurses' Health Study II (NHS II) cohorts. One hundred and forty six cases were confirmed in NHS during follow-up from 1976 to 1994, and 106 cases were confirmed in NHS II from 1989 to 1995. Skin reaction to sun exposure, sunburn history, mole counts, hair colour, family history of melanoma, parity, height and body mass index were also assessed and included in logistic regression models. A significant twofold increase in risk of melanoma (relative risk (RR) = 2.0, 95% confidence interval (CI) 1.2-3.4) was observed among current OC users compared to never users. Risk was further increased among current users with 10 or more years of use (RR = 3.4, 95% CI 1.7-7.0). Risk did not appear elevated among past OC users, even among those with longer durations of use, and risk did not decline linearly with time since last use. In conclusion, risk of premenopausal melanoma may be increased among women who are current OC users, particularly among those with longer durations of use. Further research is needed to determine whether low-dose oestrogen pills in particular are associated with an increase in risk and to describe possible interactions between OC use and sun exposure or other risk factors for melanoma.

Smoking, smoking cessation, and risk of hip fracture in women

PURPOSE

To examine the effects of cigarette smoking and smoking cessation on the risk of hip fracture in women.

PATIENTS AND METHODS

We studied 116,229 female nurses, 34 to 59 years of age at baseline in 1980, who were followed for up to 12 years. Smoking habits and the occurrence of incident hip fractures (n = 377) due to low or moderate trauma were self-reported on biennial mailed questionnaires.

RESULTS

Compared with women who had never smoked, the age-adjusted relative risk (RR) of hip fracture among current smokers was 1.3 (95% confidence interval [CI] 1.0 to 1.7). The risk of hip fracture increased linearly (P = 0.09) with greater cigarette consumption (RR = 1.6, 95% CI 1.1 to 2.3 for 25 or more cigarettes per day). These associations were somewhat reduced by adjusting for other risk factors for osteoporosis (menopausal status, use of postmenopausal estrogen, physical activity, and intakes of calcium, alcohol, and caffeine): RR = 1.2, 95% CI 0.8 to 1.3 for all current smokers; RR = 1.4, 95% CI 0.9 to 2.1 for 25 or more cigarettes per day. Relative risks were further reduced when body mass index was added to the model. There was no apparent benefit from quitting smoking until 10 years after cessation. After 10 years, former smokers had a reduced risk of hip fracture (adjusted RR = 0.7, 95% CI 0.5 to 0.9) compared with current smokers.

CONCLUSION

Smokers are at increased risk of hip fracture and their risk rises with greater cigarette consumption. Risk declines among former smokers, but the benefit is not observed until 10 years after cessation. Both the increased risk among current smokers and the decline in risk after smoking cessation are in part accounted for by differences in body weight.

Reproducibility and validity of dietary patterns assessed with a food-frequency questionnaire

BACKGROUND

Recently, the analysis of dietary patterns has emerged as a possible approach to examining diet-disease relations.

OBJECTIVE

We examined the reproducibility and validity of dietary patterns defined by factor analysis using dietary data collected with a food-frequency questionnaire (FFQ).

DESIGN

We enrolled a subsample of men (n = 127) from the Health Professionals Follow-up Study in a diet-validation study in 1986. A 131-item FFQ was administered twice, 1 y apart, and two 1-wk diet records and blood samples were collected during this 1-y interval.

RESULTS

Using factor analysis, we identified 2 major eating patterns, which were qualitatively similar across the 2 FFQs and the diet records. The first factor, the prudent dietary pattern, was characterized by a high intake of vegetables, fruit, legumes, whole grains, and fish and other seafood, whereas the second factor, the Western pattern, was characterized by a high intake of processed meat, red meat, butter, high-fat dairy products, eggs, and refined grains. The reliability correlations for the factor scores between the 2 FFQs were 0.70 for the prudent pattern and 0.67 for the Western pattern. The correlations (corrected for week-to-week variation in diet records) between the 2 FFQs and diet records ranged from 0.45 to 0.74 for the 2 patterns. In addition, the correlations between the factor scores and nutrient intakes and plasma concentrations of biomarkers were in the expected direction.

CONCLUSIONS

These data indicate reasonable reproducibility and validity of the major dietary patterns defined by factor analysis with data from an FFQ.

Vitamin K intake and hip fractures in women: a prospective study

BACKGROUND

Vitamin K mediates the gamma-carboxylation of glutamyl residues on several bone proteins, notably osteocalcin. High serum concentrations of undercarboxylated osteocalcin and low serum concentrations of vitamin K are associated with lower bone mineral density and increased risk of hip fracture. However, data are limited on the effects of dietary vitamin K.

OBJECTIVE

We investigated the hypothesis that high intakes of vitamin K are associated with a lower risk of hip fracture in women.

DESIGN

We conducted a prospective analysis within the Nurses' Health Study cohort. Diet was assessed in 72327 women aged 38-63 y with a food-frequency questionnaire in 1984 (baseline). During the subsequent 10 y of follow-up, 270 hip fractures resulting from low or moderate trauma were reported.

RESULTS

Women in quintiles 2-5 of vitamin K intake had a significantly lower age-adjusted relative risk (RR: 0.70; 95% CI: 0.53, 0.93) of hip fracture than women in the lowest quintile (< 109 microg/d). Risk did not decrease between quintiles 2 and 5 and risk estimates were not altered when other risk factors for osteoporosis, including calcium and vitamin D intakes, were added to the models. Risk of hip fracture was also inversely associated with lettuce consumption (RR: 0.55; 95% CI: 0.40, 0.78) for one or more servings per day compared with one or fewer servings per week), the food that contributed the most to dietary vitamin K intakes.

CONCLUSIONS

Low intakes of vitamin K may increase the risk of hip fracture in women. The data support the suggestion for a reassessment of the vitamin K requirements that are based on bone health and blood coagulation.

Moderate alcohol consumption and bone density among postmenopausal women

Chronic alcohol abuse is associated with low bone density and high risk of fracture. However, moderate alcohol consumption may help to maintain bone density in postmenopausal women by increasing endogenous estrogens or by promoting secretion of calcitonin. We conducted a prospective study among a sample of 188 white postmenopausal women (ages 50-74) from the Nurses' Health Study who participated in a health examination between 1993 and 1995 that included bone density assessments of the lumbar spine and proximal femur. Long-term alcohol intake was calculated as the average of the 1980 and 1990 measures from a food frequency questionnaire. Women who consumed 75 g or more of alcohol per week had significantly higher bone densities at the lumbar spine compared with non-drinking women (0.951 vs. 0.849 g/cm2, p = 0.002) after adjusting for age, body mass index (kg/m2), age at menopause, use of postmenopausal estrogens, and smoking status. Further adjustment for physical activity and daily intakes of calcium, vitamin D, protein, and caffeine did not alter the results. We also observed a linear increase in spinal bone density over increasing categories of alcohol intake (p = 0.002), suggesting that alcohol intakes of less than 75 g/week may also be of benefit. This positive association was observed among both current users and never users of postmenopausal estrogens. In contrast to the lumbar spine, femoral bone density was not higher among drinkers compared with nondrinkers, although density did increase among drinkers with increasing level of alcohol consumption. Further research is needed to determine whether moderate alcohol consumption can help to protect against spinal fractures in postmenopausal women. This finding must also be evaluated within a larger scope of the risks and benefits of alcohol on heart disease, breast cancer, and hip fractures.

Vitamin D receptor genotype and the risk of bone fractures in women

Several studies have confirmed an initial report of a relation between bone density and polymorphic forms of the calcitriol (vitamin D) receptor gene, whereas others have failed to find an association. We examined whether variants of the vitamin D receptor gene are associated with the risk of bone fracture, using a nested case-control analysis within the Nurses' Health Study cohort. The study women all were Caucasian and were 43-69 years of age when they provided a blood sample. Cases included the 54 proximal femur (hip) fractures and 163 distal radius (forearm) fractures that occurred subsequent to the blood draw. Cases and controls were genotyped by polymerase chain reaction for the BsmI polymorphism. The BB genotype, previously associated with lower bone density, was associated with a more than twofold increased risk of hip fracture compared with the bb genotype. Risk was greater for women who were older, leaner, or less physically active or who had a lower calcium intake. The heterozygous genotype was not associated with any increased risk of hip fracture, and we observed little association between vitamin D receptor genotype and forearm fracture. This study supports an association between vitamin D receptor genotype and hip fracture. It also implies that modification by other risk factors may have contributed to the conflicting results from previous studies of vitamin D receptor genotype and femoral bone density.

Use of toenail fluoride levels as an indicator for the risk of hip and forearm fractures in women

The relation between fluoride intake and risk of osteoporotic fractures remains unclear. The lack of individual measures of long-term fluoride intake has limited epidemiologic studies. We used toenail fluoride in this study as a measure of long-term intake to evaluate the relation between fluoride intake and subsequent risk of hip and distal forearm fractures. Between 1982 and 1984, we collected toenail clippings from 62,641 women in the Nurses' Health Study who were free from cancer, heart disease, stroke, and previous hip or forearm fracture. We identified fracture cases (53 proximal femur and 188 distal forearm) through subsequent biennial mailed questionnaires and matched controls to cases on year of birth. The odds ratio of hip fracture among women in the highest quartile of toenail fluoride [ > 5.50 parts per million (ppm)], compared with those in the lowest quartile (> 2.00 ppm), was 0.8 (95% confidence interval = 0.2-4.0), with adjustment for menopausal status, postmenopausal hormone use, caffeine intake, and alcohol consumption. The corresponding adjusted odds ratio for forearm fracture was 1.6 (95% confidence interval = 0.8-3.1). Further adjustment for body mass index, smoking status, and calcium and vitamin D intake did not alter these results.

Body anthropometry and the risk of hip and wrist fractures in men: results from a prospective study

Available epidemiological information on the associations between body anthropometry and the incidence of fractures in men is limited. We therefore prospectively investigated the association between body anthropometry and the incidence of hip and wrist fractures from low and moderate trauma among 43,053 men who were 40 years to 75 years of age in 1986 when they first enrolled in the Health Professionals Follow-Up Study. After 8 years of follow-up, 201 wrist fracture cases and 56 hip fracture cases were reported. Greater height was associated with significant elevations in both hip and wrist fractures, whereas nonsignificant inverse associations were observed with weight and body mass index. Men in the highest quintile of waist circumference had a relative risk (RR) of 2.57 (95% confidence interval [CI] 0.64 to 10.3) for hip fracture and 2.05 (95% CI 1.06 to 3.96) for wrist fracture when compared with men in the lowest quintile. Waist-to-hip ratio was also positively related to fracture incidence; comparing highest with lowest quintile, the RRs were 3.92 (95% CI 1.07 to 14.3) for hip fracture and 1.50 (95% CI 0.85 to 2.66) for wrist fracture. These anthropometric indicators, in particular waist-to-hip ratio, may be useful for the prediction of hip fracture in adult men.

Calcium intake and the incidence of forearm and hip fractures among men

High calcium intakes are thought to be associated with strong bones and lower risk of fractures. However, findings from epidemiologic studies have not been consistent. In addition, the vast majority of such studies were conducted among women, leading to a relative lack of data concerning men. The objective of this study therefore was to investigate the relation between adult calcium intake and risk of fractures among men in the Health Professionals Follow-up Study (HPFS). During 331,234 person-years of follow-up over an 8-y period, 201 forearm and 56 hip fractures due to low or moderate trauma were reported among 43,063 men 40-75 y of age in 1986 when they first completed a questionnaire about diet and lifestyle factors. After controlling for age, smoking status, body mass index (BMI), physical activity, alcohol consumption and total energy intake, the relative risk (RR) of forearm fractures for men in the highest quintile of calcium intake (from foods plus supplements) compared with those in the lowest quintile was 0.98 [95% confidence interval (CI) = 0.59-1.61; P for trend = 0.78]; for hip fractures, the comparable RR was 1.19 (95% CI = 0.42-3.35; P for trend = 0.58). Relative risks for consuming >2.5 glasses (600 mL) of milk per day compared with one (240 mL) or fewer per week were 1.06 (95% CI = 0.69-1.62; P for trend = 0.82) for forearm fractures and 0.97 (95% CI = 0.39-2.42; P for trend = 0.56) for hip fractures. In conclusion, these results do not support a relation between calcium intake and the incidence of forearm or hip fractures in men.

Milk, dietary calcium, and bone fractures in women: a 12-year prospective study

OBJECTIVES

This study examined whether higher intakes of milk and other calcium-rich foods during adult years can reduce the risk of osteoporotic fractures.

METHODS

This was a 12-year prospective study among 77761 women, aged 34 through 59 years in 1980, who had never used calcium supplements. Dietary intake was assessed with a food-frequency questionnaire in 1980, 1984, and 1986. Fractures of the proximal femur (n = 133) and distal radius (n = 1046) from low or moderate trauma were self-reported on biennial questionnaires.

RESULTS

We found no evidence that higher intakes of milk or calcium from food sources reduce fracture incidence. Women who drank two or more glasses of milk per day had relative risks of 1.45 for hip fracture (95% confidence interval [CI] = 0.87, 2.43) and 1.05 for forearm fracture (95% CI = 0.88, 1.25) when compared with women consuming one glass or less per week. Likewise, higher intakes of total dietary calcium or calcium from dairy foods were not associated with decreased risk of hip or forearm fracture.

CONCLUSIONS

These data do not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures.

A prospective study of thiazide use and fractures in women

Thiazide diuretics reduce urinary calcium and may inhibit bone resorption, and hence may help to attenuate age-related bone loss and to lower the risk of osteoporotic fracture. We followed 83728 women, who were 36-61 years of age at baseline in 1982, for 10 years with biennial mailed questionnaires on which they reported incident fractures, use of thiazide diuretics, and other medical behavioral information. From descriptions of fracture sites and circumstances, 251 hip (proximal femur) and 1594 forearm (distal radius) fractures were identified as low or moderate trauma events. After controlling for age, body mass index, menopausal status, postmenopausal hormone use, cigarette smoking and dietary factors, we observed a statistically significant 22% reduction in the risk of forearm fractures among current thiazide users compared with women who reported no thiazide use. Risk appeared to decline with longer duration of use, reaching a 37% reduction in risk among women who had been using thiazides for 8 or more years. For hip fractures, thiazide use was protective among the postmenopausal women (relative risk = 0.69, 95% confidence interval 0.48-0.99). We conclude that the potential benefit of thiazide diuretics for osteoporosis should be considered when prescribing antihypertensive treatment.

Protein consumption and bone fractures in women

Dietary protein increases urinary calcium losses and has been associated with higher rates of hip fracture in cross-cultural studies. However, the relation between protein and risk of osteoporotic bone fractures among individuals has not been examined in detail. In this prospective study, usual dietary intake was measured in 1980 in a cohort of 85,900 women, aged 35-59 years, who were participants in the Nurses' Health Study. A mailed food frequency questionnaire was used and incident hip (n = 234) and distal forearm (n = 1,628) fractures were identified by self-report during the following 12 years. Information on other factors related to osteoporosis, including obesity, use of postmenopausal estrogen, smoking, and physical activity, was collected on biennial questionnaires. Dietary measures were updated in 1984 and 1986. Protein was associated with an increased risk of forearm fracture (relative risk (RR) = 1.22, 95% confidence interval (Cl) 1.04-1.43, p for trend = 0.01) for women who consumed more than 95 g per day compared with those who consumed less than 68 g per day. A similar increase in risk was observed for animal protein, but no association was found for consumption of vegetable protein. Women who consumed five or more servings of red meat per week also had a significantly increased risk of forearm fracture (RR = 1.23, 95% Cl 1.01-1.50) compared with women who ate red meat less than once per week. Recall of teenage diet did not reveal any increased risk of forearm fracture for women with higher consumption of animal protein or red meat during this earlier period of life. No association was observed between adult protein intake and the incidence of hip fractures, though power to assess this association was low.

Body height and hip fracture: a cohort study of 90,000 women

BACKGROUND

Hip fractures are a major public health problem. Recent studies have noted a connection between body height and hip fracture.

METHODS

We investigated the relationship between body height and hip fracture using a prospective cohort of over 92,000 American, predominantly white, female nurses who were followed for 10 years, from June 1980 to June 1990. The women, participants in the Nurses Health Study, were aged 35-59 in 1980.

RESULTS

Women 5'8" or taller were more than twice as likely as women under 5'2" to sustain a hip fracture, after accounting for age, body mass index, cigarette smoking and alcohol consumption (multivariate relative risk 2.40, 95% confidence interval: 1.43-4.02; P for trend < 0.0001).

CONCLUSION

Height appears to be an important independent risk factor for hip fracture among American women. Height should be included as a confounder in studies of hip fracture, and taller, elderly women should be advised to consider preventive measures.

Risk factors for hip fracture in US men aged 40 through 75 years

Relatively few studies have examined risk factors for hip fracture among men. This study analyzes data from the Health Professionals Follow-up Study, a prospective study of approximately 50,000 men who were between the ages of 40 and 75 years in 1986. Body mass index, smoking status, and alcohol consumption were not associated with hip fracture in this population. However, age and height were related to hip fracture. Men who were 65 and older had a significantly higher risk of sustaining a hip fracture than younger adults. Men 6 feet or taller were more than twice as likely to sustain a hip fracture as those under 5 feet, 9 inches.

Risk factors for wrist fracture: effect of age, cigarettes, alcohol, body height, relative weight, and handedness on the risk for distal forearm fractures in men

Fractures of the distal forearm (wrist) are among the most common of all fractures. While evidence exists concerning risk factors for wrist fracture among women, little is known about risk factors among men. This study examines the relation of lifestyle characteristics (cigarette smoking, alcohol consumption, relative weight) as well as body height and handedness to the risk for fracture in a male population that has been followed up for 6 years. The 51,529 men, who were between the ages of 40 and 75 years in 1986, were participants in the Health Professionals Follow-up Study, a national prospective cohort study. In 271,552 person-years of follow-up, 271 respondents reported a wrist fracture. The risk for wrist fracture in this population did not vary with age. Cigarette smoking, alcohol consumption, body height, and relative weight also were not related to risk for wrist fracture. Handedness, which was divided into four mutually exclusive categories (right-handed, left-handed, forced to change, and ambidextrous), was significantly associated with wrist fracture. Left-handers had a multivariate relative risk for wrist fracture 1.56 times that of right-handers (95% confidence interval 1.02-2.37), and men who reported they had been forced to change from left-handed to right-handed had a multivariate relative risk 2.47 times greater than right-handers (95 percent confidence interval 1.21-5.04).

Simulated validation of a brief food frequency questionnaire

Nutrient assessment by the brief 45-item food frequency questionnaire used in the New York State Cohort was simulated by reducing the food list and frequency-of-use categories of the extensive 131-food item semiquantitative questionnaire used in the Health Professionals Follow-up Study. As a validation of the brief questionnaire, daily nutrient intakes were calculated following simulation procedures for 127 men who completed the extensive questionnaire, and the values were compared with those from two 1-week diet records in the same population. Deattenuated correlation coefficients for 25 energy-adjusted nutrient values ranged from 0.12 for iron to 0.76 for vitamin C (mean, 0.26). The brief questionnaire appears reasonably effective in assessing relative dietary intakes of total fat, saturated fat, monounsaturated fat, carbohydrate, dietary fiber, carotene, vitamin C, calcium, potassium, and magnesium. Modest improvements in the correlations for most nutrients were seen when the number of frequency-of-use categories was increased. Correlations decreased when nutrient intakes were calculated using regression coefficients instead of a conventional nutrient database.

Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire

Few food frequency questionnaires have been evaluated for their ability to assess intakes of individual foods that may be related to disease independently of their nutrient content. The reproducibility and validity of food intake measurements by a 131-item semiquantitative food frequency questionnaire were evaluated in a sample of 127 men from the Health Professionals Follow-up Study, a large longitudinal study of diet and disease. Each subject completed two questionnaires 1 year apart and two 1-week diet records 6 months apart during the intervening year. Pearson correlations assessing reproducibility between food intakes from the two questionnaires ranged from .31 for pie to .92 for coffee (mean = .59). Validity was measured by comparing food intakes from the second questionnaire with those from the diet records. Pearson correlations corrected for within-person weekly variation in diet record data ranged from .17 for other nuts to .95 for bananas (mean = .63). Large within-person variation precluded the calculation of accurate validity correlations for 29 foods. As we previously observed in women, the foods most often overreported were fruits and vegetables, and meats and dairy products were most often underreported. With few exceptions, reasonable levels of reproducibility and validity were observed for intake of individual foods in this extensive food frequency questionnaire.